AQA GCSE Combined Science Foundation: grade by grade

Every skill, from the first marks to the top grade. For each grade you also need the skills for the grades below it. Tick them off in the app's Notes section.

Grade 3

Grade 3 checklist (PDF)

Name eukaryotic and prokaryotic cells Animal and plant cells are eukaryotic; bacterial cells are prokaryotic. Eukaryotes and prokaryotes
Name the parts of an animal cell Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Animal and plant cells
Name the extra structures in plant cells Chloroplasts, a permanent vacuole filled with cell sap, and a cell wall made of cellulose. Animal and plant cells
Name specialised animal and plant cells Sperm, nerve and muscle cells in animals; root hair, xylem and phloem cells in plants. Cell specialisation
State what cell differentiation is Differentiation is the process by which a cell becomes specialised for a particular function. Cell differentiation
State what magnification means How many times bigger the image is than the real object. Microscopy
State where chromosomes are found In the nucleus of a cell. Chromosomes
State what mitosis produces Two genetically identical cells. Mitosis and the cell cycle
State what a stem cell is An undifferentiated cell that can make more cells of the same type and can differentiate into other types of cell. Stem cells
Define diffusion The net movement of particles from an area of higher concentration to an area of lower concentration. Diffusion
Define osmosis The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane. Osmosis
State what active transport is The movement of substances from a more dilute solution to a more concentrated solution, against a concentration gradient. Active transport
Put the levels of organisation in order From smallest to largest: cell → tissue → organ → organ system → organism. Principles of organisation
Name the organs of the digestive system Mouth and salivary glands, oesophagus, stomach, liver, gall bladder, pancreas, small intestine and large intestine. The human digestive system
Name the three types of blood vessel Arteries carry blood away from the heart, veins carry blood back to the heart, and capillaries link them inside tissues. The heart and blood vessels
Name the four components of blood Plasma, red blood cells, white blood cells and platelets. Blood
Name the vessels that supply heart muscle The coronary arteries supply the heart muscle with oxygenated blood. Coronary heart disease: a non-communicable disease
Define health Health is the state of physical and mental well-being. Health issues
Define a risk factor A factor linked to an increased rate of a disease, such as part of a person's lifestyle or a substance in their body or environment. The effect of lifestyle on some non-communicable diseases
Define cancer Cancer is the result of changes in cells that lead to uncontrolled growth and division. Cancer
Name the tissues in a leaf Upper and lower epidermis, palisade mesophyll, spongy mesophyll, xylem and phloem, with guard cells around the stomata. Plant tissues
Name the parts of the plant transport system The roots, stem and leaves form an organ system; xylem carries water and phloem carries sugars. Plant organ system
Define a pathogen A pathogen is a microorganism that causes infectious (communicable) disease. Communicable (infectious) diseases
Name the four types of pathogen Viruses, bacteria, fungi and protists; they can infect both animals and plants. Communicable (infectious) diseases
Name viral diseases of humans and plants Measles and HIV in humans; tobacco mosaic virus (TMV) in plants. Viral diseases
Name two bacterial diseases Salmonella food poisoning and gonorrhoea, a sexually transmitted disease. Bacterial diseases
Name a fungal disease of plants Rose black spot is a fungal disease of roses. Fungal diseases
Name a disease caused by a protist Malaria is caused by a single-celled protist. Protist diseases
Name the body's non-specific defences The skin, the nose, the trachea and bronchi, and the stomach. Human defence systems
State what a vaccine contains Small quantities of a dead or inactive form of a pathogen. Vaccination
State what antibiotics do Antibiotics, such as penicillin, kill infective bacteria inside the body, curing bacterial diseases. Antibiotics and painkillers
State what painkillers do Painkillers treat the symptoms of a disease but do not kill pathogens. Antibiotics and painkillers
Match drugs to their original sources Digitalis from foxgloves, aspirin from willow, and penicillin from Penicillium mould (discovered by Alexander Fleming). Discovery and development of drugs
Write the word equation for photosynthesis carbon dioxide + water → glucose + oxygen, with light written above the arrow. Photosynthetic reaction
State where photosynthesis takes place In the chloroplasts of plant and algal cells, where chlorophyll absorbs light. Photosynthetic reaction
Name the factors affecting photosynthesis rate Temperature, light intensity, carbon dioxide concentration and the amount of chlorophyll. Rate of photosynthesis
List the five uses of glucose Respiration, starch for storage, fats or oils for storage, cellulose for cell walls, and amino acids for proteins. Uses of glucose from photosynthesis
State why organisms need energy For chemical reactions that build larger molecules, for movement and for keeping warm. Aerobic and anaerobic respiration
Write the word equation for aerobic respiration glucose + oxygen → carbon dioxide + water. Aerobic and anaerobic respiration
State how exercise changes heart and breathing Heart rate, breathing rate and breath volume all increase. Response to exercise
Define metabolism Metabolism is the sum of all the reactions in a cell or the body. Metabolism
Define homeostasis Regulating the internal conditions of a cell or organism to keep them at the optimum, in response to internal and external changes. Homeostasis
Name conditions controlled by homeostasis In humans: blood glucose concentration, body temperature and water levels. Homeostasis
State what the nervous system does It lets you react to your surroundings and coordinates your behaviour. The human nervous system
Define a hormone A chemical secreted by a gland directly into the bloodstream, which carries it to a target organ. Human endocrine system
Name the organ that controls blood glucose The pancreas monitors and controls blood glucose concentration. Control of blood glucose concentration
Name the main male and female hormones Testosterone from the testes; oestrogen from the ovaries. Hormones in human reproduction
Name hormonal and non-hormonal contraceptive methods E.g. the pill, implant, condom, diaphragm, IUD, spermicide, abstinence and sterilisation. Contraception
Name the gametes in animals and plants Animals: sperm and egg cells. Flowering plants: pollen and egg cells. Sexual and asexual reproduction
State how many parents each type needs Sexual reproduction needs two parents; asexual reproduction needs only one. Sexual and asexual reproduction
State where and why meiosis happens Cells in the reproductive organs divide by meiosis to form gametes. Meiosis
State where DNA is found The genetic material in the nucleus is a chemical called DNA, contained in chromosomes. DNA and the genome
Define dominant and recessive alleles A dominant allele is expressed even with one copy; a recessive allele is expressed only with two copies. Genetic inheritance
Describe polydactyly and cystic fibrosis Polydactyly is having extra fingers or toes; cystic fibrosis is a disorder of cell membranes. Inherited disorders
State the number of chromosome pairs Ordinary human body cells contain 23 pairs of chromosomes. Sex determination
Define variation Differences in the characteristics of individuals in a population. Variation
Define evolution A change in the inherited characteristics of a population over time through natural selection. Evolution
Define selective breeding Humans breeding plants and animals for particular genetic characteristics. Selective breeding
State that evolution is widely accepted The theory of evolution by natural selection is now widely accepted. Evidence for evolution
Define a fossil The remains of organisms from millions of years ago, which are found in rocks. Fossils
Define extinction A species is extinct when there are no remaining individuals of that species still alive. Extinction
Name an antibiotic-resistant bacterium MRSA is resistant to antibiotics. Resistant bacteria
List the Linnaean groups in order Kingdom, phylum, class, order, family, genus, species. Classification of living organisms
Define population, community, habitat and ecosystem A population is one species in a habitat, a community is all the populations there, and an ecosystem is the community interacting with the non-living environment. Communities
Define an abiotic factor A non-living factor in the environment that can affect a community. Abiotic factors
Define a biotic factor A living factor, such as another organism, that can affect a community. Biotic factors
Define an adaptation A feature that helps an organism survive in the conditions where it normally lives. Adaptations
Name producers and consumers in a food chain The producer comes first, then the primary, secondary and tertiary consumers. Levels of organisation
State that materials are recycled in ecosystems Materials cycle through the living and non-living parts of an ecosystem, providing the building blocks for new organisms. How materials are cycled
Define biodiversity The variety of all the different species of organisms on Earth, or within an ecosystem. Biodiversity
Name sources of water, air and land pollution Water: sewage, fertiliser, toxic chemicals. Air: smoke, acidic gases. Land: landfill, toxic chemicals. Waste management
Name ways humans use land Building, quarrying, farming and dumping waste. Land use
Define deforestation Cutting down large areas of forest so the land can be used for something else. Deforestation
Name two gases that contribute to global warming Carbon dioxide and methane. Global warming
Name programmes that protect biodiversity Breeding programmes, protecting rare habitats, hedgerows and field margins, reducing deforestation and carbon dioxide emissions, and recycling. Maintaining biodiversity
Tell elements from compounds using formulae An element's formula has one symbol (Fe, O₂); a compound's formula has two or more different symbols (CO₂, NaCl). Atoms, elements and compounds
Recall symbols of the first 20 elements Also the Group 1 and Group 7 elements and others in the course, with the correct capital and lower-case letters. Atoms, elements and compounds
Define a mixture Two or more elements or compounds that are not chemically combined together. Mixtures
State that models change with new evidence A scientific model may be changed or replaced when new experimental evidence doesn't fit it. The development of the model of the atom
Recall the charges of subatomic particles Proton +1, neutron 0, electron −1. Relative electrical charges of subatomic particles
State where each particle is found Protons and neutrons are in the nucleus; electrons are in shells around it. Relative electrical charges of subatomic particles
Recall relative masses of subatomic particles Proton 1, neutron 1, electron very small. Size and mass of atoms
Recall how many electrons each shell holds For the first 20 elements: 2 in the first shell, then up to 8 in the second and 8 in the third. Electronic structure
Identify groups and periods Groups are the vertical columns; periods are the horizontal rows. The periodic table
State how early tables were ordered By atomic weight, because protons, neutrons and electrons had not been discovered. Development of the periodic table
Locate metals and non-metals in the table Metals are on the left and towards the bottom; non-metals are on the right and towards the top. Metals and non-metals
Name Group 0 and some of its elements The noble gases: helium, neon, argon, krypton, xenon and radon. Group 0
Explain the name 'alkali metals' They react with water to form hydroxides that dissolve to give alkaline solutions. Group 1
Recall the halogens and their states At room temperature chlorine is a green gas, bromine a red-brown liquid and iodine a grey-black solid. Group 7
Name the three types of strong bond Ionic, covalent and metallic. Chemical bonds
State that metals lose and non-metals gain electrons Metal atoms lose outer electrons to form positive ions; non-metal atoms gain electrons to form negative ions. Ionic bonding
Describe an ionic compound as a giant structure It is a giant structure (lattice) of ions arranged in a regular pattern. Ionic compounds
Describe a covalent bond as a shared pair A covalent bond is a pair of electrons shared between two atoms. Covalent bonds are strong. Covalent bonding
State that metals have giant structures The atoms in a metal are arranged in a regular pattern in a giant structure. Metallic bonding
Name the changes of state Melting and freezing happen at the melting point; boiling and condensing happen at the boiling point. The three states of matter
Recall the four state symbols (s) solid, (l) liquid, (g) gas, (aq) aqueous: dissolved in water. State symbols
State that ionic compounds have high melting points Ionic compounds such as sodium chloride are solids at room temperature with high melting and boiling points. Properties of ionic compounds
State that small molecules have low boiling points Substances made of small molecules are usually gases or liquids at room temperature. Properties of small molecules
State that polymers have very large molecules Polymer molecules are long chains made of many repeating units. Polymers
Name examples of giant covalent structures Diamond and graphite (both forms of carbon) and silicon dioxide (silica). Giant covalent structures
State that pure metals can be bent and shaped The atoms in a pure metal are arranged in layers. Properties of metals and alloys
State that metals conduct electricity and heat Metals are good conductors of electricity and of thermal energy. Metals as conductors
State that diamond is a form of carbon Diamond is made only of carbon atoms, in a giant covalent structure. Diamond
Describe graphite as layers of carbon atoms Graphite is made of layers of carbon atoms arranged in hexagonal rings. Graphite
Describe graphene as one layer of graphite Graphene is a single layer of carbon atoms in hexagonal rings, one atom thick. Graphene and fullerenes
State the law of conservation of mass No atoms are lost or made in a reaction, so the mass of the products equals the mass of the reactants. Conservation of mass and balanced chemical equations
Count the atoms in a formula Multiply the small numbers by the big number in front, e.g. 2H₂O contains 4 hydrogen atoms and 2 oxygen atoms. Conservation of mass and balanced chemical equations
Read relative atomic masses from the periodic table A_r is the larger of the two numbers in each box, e.g. O = 16, Na = 23. Relative formula mass
State that gases can enter or leave In an open container, gases can escape into the air or react from the air. Mass changes when a reactant or product is a gas
Calculate a mean from repeat readings Add up the results, leaving out any anomalous ones, and divide by how many you added. Chemical measurements
Recall the unit of concentration Mass of solute per volume of solution, usually grams per dm³ (g/dm³). Concentration of solutions
Name the oxide formed by a metal A metal reacting with oxygen forms the metal oxide, e.g. magnesium + oxygen → magnesium oxide. Metal oxides
Recall the order of the reactivity series Potassium, sodium, lithium, calcium, magnesium, (carbon), zinc, iron, (hydrogen), copper, from most to least reactive. The reactivity series
Explain why gold is found as the metal Gold is so unreactive that it is found in the Earth as the metal itself, not as a compound. Extraction of metals and reduction
Name the products of metal + acid A salt and hydrogen, e.g. magnesium + hydrochloric acid → magnesium chloride + hydrogen. Reactions of acids with metals
Name the salt type from each acid Hydrochloric acid gives chlorides, nitric acid gives nitrates and sulfuric acid gives sulfates. Neutralisation of acids and salt production
Name reactants needed to make a salt For example, copper(II) oxide and sulfuric acid make copper(II) sulfate. Soluble salts
Use pH to classify solutions Below 7 is acidic, 7 is neutral and above 7 is alkaline. The pH scale and neutralisation
Name the electrodes and their charges The cathode is the negative electrode and the anode is the positive electrode. The process of electrolysis
State the products from molten lead bromide Lead is produced at the cathode and bromine at the anode. Electrolysis of molten ionic compounds
Define exothermic and endothermic reactions Exothermic reactions transfer energy to the surroundings so their temperature rises; endothermic reactions take in energy so their temperature falls. Energy transfer during exothermic and endothermic reactions
Give examples of exothermic reactions Combustion, many oxidation reactions and neutralisation are all exothermic. Energy transfer during exothermic and endothermic reactions
State what activation energy is The minimum amount of energy that particles must have to react when they collide. Reaction profiles
Say what the rate of reaction measures Rate is how quickly a reactant is used up or a product is formed. Calculating rates of reactions
Name the five factors that affect rate Concentration of solutions, pressure of gases, surface area of solids, temperature and the presence of a catalyst. Factors which affect the rates of chemical reactions
State that particles must collide to react A reaction can only happen when reactant particles collide with each other. Collision theory and activation energy
State what a catalyst does It increases the rate of a reaction but is not used up. Catalysts
Recognise the reversible reaction symbol ⇌ The ⇌ symbol shows that a reaction can go in both directions. Reversible reactions
Recall what exothermic and endothermic mean Exothermic reactions transfer energy to the surroundings; endothermic reactions take in energy from the surroundings. Energy changes and reversible reactions
State what crude oil is A finite resource found in rocks: the remains of an ancient biomass, mainly plankton, that was buried in mud. Crude oil, hydrocarbons and alkanes
Define a hydrocarbon A compound whose molecules are made of hydrogen and carbon atoms only. Crude oil, hydrocarbons and alkanes
Name fuels produced from crude oil Petrol, diesel oil, kerosene, heavy fuel oil and liquefied petroleum gases (LPG). Fractional distillation and petrochemicals
Name materials made by the petrochemical industry Solvents, lubricants, polymers and detergents. Fractional distillation and petrochemicals
Name the products of complete combustion A hydrocarbon burns completely in oxygen to form carbon dioxide and water. Properties of hydrocarbons
Define cracking Breaking down large hydrocarbon molecules into smaller, more useful molecules. Cracking and alkenes
Define a pure substance in chemistry A single element or a single compound, not mixed with any other substance. Pure substances
Define a formulation A mixture that has been designed as a useful product. Formulations
Give examples of formulations Fuels, cleaning agents, paints, medicines, alloys, fertilisers and foods. Formulations
Tell mixtures from pure substances on chromatograms A mixture gives two or more spots; a pure substance gives a single spot. Chromatography
Describe the test for hydrogen Hold a burning splint at the open end of a test tube of the gas. Test for hydrogen
State the positive result for hydrogen Hydrogen burns rapidly with a pop sound (a 'squeaky pop'). Test for hydrogen
Describe the test for oxygen Put a glowing splint into a test tube of the gas. Test for oxygen
State the positive result for oxygen The glowing splint relights (bursts back into flame). Test for oxygen
Describe the test for carbon dioxide Bubble the gas through limewater, or shake the gas with limewater. Test for carbon dioxide
State the positive result for carbon dioxide The limewater turns milky (cloudy). Test for carbon dioxide
Describe the test for chlorine Put damp litmus paper into the gas. Test for chlorine
State the positive result for chlorine The litmus paper is bleached and turns white. Test for chlorine
Name the two main gases in air Nitrogen makes up about four-fifths of the air and oxygen about one-fifth. The proportions of different gases in the atmosphere
Give the percentages of nitrogen and oxygen Air is about 80% nitrogen and about 20% oxygen. The proportions of different gases in the atmosphere
Say where the early atmosphere came from Intense volcanic activity during the Earth's first billion years released the gases that formed it. The Earth's early atmosphere
Name the process that produced the oxygen Photosynthesis by algae and plants produced the oxygen that is now in the atmosphere. How oxygen increased
Name a process that removed carbon dioxide Photosynthesis by algae and plants took carbon dioxide out of the atmosphere. How carbon dioxide decreased
Name three greenhouse gases Water vapour, carbon dioxide and methane are greenhouse gases. Greenhouse gases
Give two activities that release carbon dioxide Burning fossil fuels and deforestation both increase the carbon dioxide in the atmosphere. Human activities which contribute to an increase in greenhouse gases in the atmosphere
State a major cause of climate change An increase in the average global temperature is a major cause of climate change. Global climate change
Give one way to reduce carbon dioxide emissions For example, generate electricity from renewable resources instead of burning fossil fuels. The carbon footprint and its reduction
Name the products of complete combustion A fuel containing carbon and hydrogen forms carbon dioxide and water when it burns in plenty of oxygen. Atmospheric pollutants from fuels
State that carbon monoxide is toxic Carbon monoxide is a toxic (poisonous) gas. Properties and effects of atmospheric pollutants
State what humans use Earth's resources for To provide warmth, shelter, food and transport. Using the Earth's resources and sustainable development
State what potable water means Potable water is water that is safe to drink. Potable water
Say why waste water must be treated Towns and industry produce large amounts of waste water that must be treated before it is released into the environment. Waste water treatment
Name the four stages of an LCA Extracting and processing raw materials, manufacturing and packaging, use and operation, and disposal. Life cycle assessment
State the three ways to reduce resource use Reduce use, reuse and recycle. Ways of reducing the use of resources
Define a system A system is an object or a group of objects that you choose to study, e.g. a ball and the Earth. Energy stores and systems
Name the main energy stores Kinetic, gravitational potential, elastic potential, thermal (internal), chemical, magnetic, electrostatic and nuclear. Energy stores and systems
Recall the kinetic and gravitational energy equations E_k = ½ m v² and E_p = m g h: the specification says you must be able to recall both. Changes in energy
Name what affects the energy needed to heat The energy needed depends on the mass, the material and the temperature rise. Energy changes in systems
State the unit of power Power is measured in watts (W); 1 W is 1 joule transferred per second. Power
State the law of conservation of energy Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed. Energy transfers in a system
Identify useful and wasted energy transfers E.g. for a lamp, light is the useful output and heating the surroundings is wasted. Efficiency
List the main energy resources Fossil fuels (coal, oil, gas), nuclear fuel, bio-fuel, wind, hydro-electricity, geothermal, the tides, the Sun and water waves. National and global energy resources
Define a renewable energy resource A resource that is being (or can be) replenished as it is used. National and global energy resources
Name common components from their symbols Recognise the cell, battery, switch, lamp, resistor, ammeter and voltmeter symbols. Standard circuit diagram symbols
State that current is a flow of charge Electric current is a flow of electrical charge around a closed circuit. Electrical charge and current
Give the units of charge, current, time Charge in coulombs (C), current in amperes (A) and time in seconds (s). Electrical charge and current
State the unit of resistance Resistance is measured in ohms (Ω). Current, resistance and potential difference
Recall that an LDR's resistance falls in light The resistance of an LDR decreases as light intensity increases. Resistors
Tell series and parallel circuits apart Series: one loop, one path. Parallel: two or more branches connected across the same two points. Series and parallel circuits
State that mains electricity is ac The mains supply is an alternating current (ac) supply. Direct and alternating potential difference
Recall the UK mains frequency and pd The UK domestic supply has a frequency of 50 Hz and is about 230 V. Direct and alternating potential difference
Recall the colours of the three wires Live is brown, neutral is blue, earth is green and yellow stripes. Mains electricity
State the unit of power Power is measured in watts (W); 1 W is 1 joule per second. Power
Describe energy transfers in simple appliances e.g. a kettle transfers energy electrically from the mains to the thermal energy store of the water. Energy transfers in everyday appliances
Describe what the National Grid is A system of cables and transformers linking power stations to consumers. The National Grid
Draw particle diagrams for the three states Solid: particles touching in regular rows; liquid: particles touching but jumbled; gas: particles far apart and random. Density of materials
Name the changes of state Melting, freezing, boiling, evaporating, condensing and sublimating. Changes of state
State that heating increases the particles' energy Heating a system transfers energy to its particles, so the energy they store increases. Internal energy
Describe the motion of gas molecules They are in constant random motion, moving in all directions. Particle motion in gases
Name the three particles in an atom Protons and neutrons are in the nucleus; electrons are arranged around the nucleus. The structure of an atom
State what atomic number means The atomic number is the number of protons in the nucleus. Mass number, atomic number and isotopes
Put the models of the atom in order Tiny spheres, plum pudding, nuclear model, Bohr's energy levels, then protons and neutrons. The development of the model of the atom
Name the types of nuclear radiation Alpha particles (α), beta particles (β), gamma rays (γ) and neutrons (n). Radioactive decay and nuclear radiation
Give precautions for handling radioactive sources Use tongs, wear gloves, keep the source in a lead-lined box and spend as little time near it as possible. Radioactive contamination
Define scalar and vector quantities A scalar has magnitude only; a vector has magnitude and an associated direction. Scalar and vector quantities
Define a force as a push or pull A force acts on an object because of its interaction with another object, and is measured in newtons (N). Contact and non-contact forces
Name examples of contact forces Friction, air resistance, tension and normal contact force act when objects are touching. Contact and non-contact forces
Define weight as the force due to gravity Weight is measured in newtons (N); mass is measured in kilograms (kg). Gravity
Define resultant force A single force that has the same effect as all the original forces acting together. Resultant forces
State that work done is energy transferred When a force moves an object through a distance, energy is transferred and work is done. Work done and energy transfer
Explain why more than one force is needed To stretch, bend or compress an object, forces must act on it in different directions. Forces and elasticity
State that distance is a scalar Distance is how far an object moves; it does not involve direction. Distance and displacement
State that speed is a scalar Speed is the distance travelled per unit time and has no direction. Speed
Define velocity The velocity of an object is its speed in a given direction. Velocity
Describe motion from a distance–time graph A horizontal line means stationary; a straight sloping line means constant speed. The distance–time relationship
Recognise balanced forces on a diagram Equal-sized arrows in opposite directions mean the resultant force is zero. Newton's First Law
Define stopping distance as thinking plus braking Thinking distance is covered during the reaction time; braking distance is covered while the brakes act. Stopping distance
Recall typical reaction times Typical reaction times range from 0.2 s to 0.9 s. Reaction time
Name factors that increase braking distance Higher speed, wet or icy roads, worn brakes and worn tyres. Factors affecting braking distance 1
Give examples of transverse and longitudinal waves Transverse: ripples on water and all electromagnetic waves, such as light. Longitudinal: sound waves in air. Transverse and longitudinal waves
Label amplitude and wavelength on a diagram Amplitude: from the undisturbed position to a crest (or trough). Wavelength: one complete wave, e.g. crest to crest. Properties of waves
Name the parts of the EM spectrum in order Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays. Types of electromagnetic waves
State that EM waves are transverse EM waves are transverse waves that transfer energy from a source to an absorber. Types of electromagnetic waves
Name the EM waves that harm body tissue Ultraviolet, X-rays and gamma rays can have hazardous effects on human body tissue. Properties of electromagnetic waves 2
Match each EM wave to a use E.g. radio waves: television and radio; X-rays: medical imaging. Uses and applications of electromagnetic waves
State where a magnet's forces are strongest The magnetic forces are strongest at the poles: the north (seeking) pole and the south (seeking) pole. Poles of a magnet
Predict attraction or repulsion between two poles Like poles (N and N, or S and S) repel; unlike poles (N and S) attract. Poles of a magnet
Name the four magnetic materials Iron, steel, cobalt and nickel are always attracted by a magnet. Magnetic fields
State that a current produces a magnetic field When a current flows through a wire, a magnetic field is produced around the wire. Electromagnetism

Grade 4

Grade 4 checklist (PDF)

Describe the structure of a bacterial cell Cytoplasm and a cell membrane inside a cell wall, a single loop of DNA not in a nucleus, and often plasmids. Eukaryotes and prokaryotes
State the function of each structure e.g. mitochondria are where aerobic respiration happens; ribosomes are where proteins are made. Animal and plant cells
State the function of each specialised cell e.g. a nerve cell carries electrical impulses; phloem carries dissolved sugars. Cell specialisation
Say when animal and plant cells differentiate Most animal cells differentiate at an early stage; many plant cells can differentiate throughout life. Cell differentiation
Calculate the total magnification of a microscope Multiply the eyepiece lens magnification by the objective lens magnification, e.g. ×10 and ×40 give ×400. Microscopy
Compare light and electron microscopes Electron microscopes have much higher magnification and resolution; light microscopes can show living cells in colour. Microscopy
Describe what chromosomes are made of Chromosomes are made of DNA, and each chromosome carries a large number of genes. Chromosomes
State the chromosome number in human cells Body cells have 23 pairs (46 in total); sperm and egg cells have 23 single chromosomes. Chromosomes
Name the three stages of the cell cycle Growth and DNA replication; mitosis; division of the cytoplasm and cell membrane. Mitosis and the cell cycle
Name where stem cells are found In embryos, in adult bone marrow, and in the meristems of plants. Stem cells
Give examples of diffusion in living things Oxygen and carbon dioxide in gas exchange; urea from cells into the blood plasma. Diffusion
Predict the direction of water movement Water moves from the more dilute solution into the more concentrated solution. Osmosis
State where the energy comes from Active transport needs energy from respiration. Active transport
Define tissue, organ and organ system A tissue is a group of cells with a similar structure and function, an organ is a group of tissues working together, and an organ system is a group of organs working together. Principles of organisation
State what each digestive enzyme produces Amylase turns starch into sugars, proteases turn proteins into amino acids, and lipases turn lipids into fatty acids and glycerol. The human digestive system
Describe the food tests and positive results Benedict's turns from blue to brick red when heated with sugar, iodine from orange-brown to blue-black with starch, and Biuret from blue to purple with protein. The human digestive system
Label the heart's chambers and main vessels Right and left atria and ventricles, the vena cava, pulmonary artery, pulmonary vein, aorta and coronary arteries. The heart and blood vessels
State the function of each component Plasma transports dissolved substances, red blood cells carry oxygen, white blood cells defend against pathogens and platelets help the blood clot. Blood
Describe what happens in coronary heart disease Layers of fatty material build up inside the coronary arteries and narrow them. Coronary heart disease: a non-communicable disease
Tell communicable and non-communicable diseases apart Communicable diseases are caused by pathogens and can spread; non-communicable diseases cannot be passed from one person to another. Health issues
Match risk factors to the diseases they affect Diet, smoking and lack of exercise → cardiovascular disease; obesity → type 2 diabetes; alcohol → liver and brain; smoking → lung disease and lung cancer; carcinogens → cancer. The effect of lifestyle on some non-communicable diseases
Describe a benign tumour A growth of abnormal cells contained in one area, usually within a membrane, that does not invade other parts of the body. Cancer
Label a leaf cross-section From top to bottom: waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll with air spaces and veins, lower epidermis with stomata. Plant tissues
State where meristem tissue is found At the growing tips of shoots and roots, where cells divide to make new cells. Plant tissues
Define transpiration and translocation Transpiration is the loss of water vapour from the leaves; translocation is the movement of dissolved sugars through the phloem. Plant organ system
Describe how pathogens are spread By direct contact, by water and by air, and also in food, in body fluids and by vectors. Communicable (infectious) diseases
Describe the symptoms and spread of measles Fever and a red skin rash; it is spread by breathing in droplets from coughs and sneezes. Viral diseases
Describe how HIV is spread By sexual contact or by exchange of body fluids such as blood, e.g. when drug users share needles. Viral diseases
Give the symptoms of Salmonella food poisoning Fever, abdominal cramps, vomiting and diarrhoea, caused by the bacteria and the toxins they secrete. Bacterial diseases
Give the symptoms of gonorrhoea A thick yellow or green discharge from the vagina or penis, and pain on urinating. Bacterial diseases
Describe the symptoms of rose black spot Purple or black spots develop on the leaves, which often turn yellow and drop early. Fungal diseases
State how rose black spot is spread It is spread in the environment by water (e.g. splashing rain) or by wind. Fungal diseases
Describe the main symptom of malaria Recurrent episodes of fever (the fever keeps coming back); malaria can be fatal. Protist diseases
Identify the vector of malaria Mosquitoes carry the protist and pass it to people when they bite them. Protist diseases
Describe how each defence stops pathogens Skin is a barrier; mucus traps pathogens; cilia move the mucus away; stomach acid kills pathogens. Human defence systems
Name three ways white blood cells defend Phagocytosis, producing antibodies and producing antitoxins. Human defence systems
Describe what a vaccine makes the body do It stimulates white blood cells to produce antibodies against the pathogen. Vaccination
Explain why antibiotics don't treat viral diseases Antibiotics kill bacteria but cannot kill viruses. Antibiotics and painkillers
State what new drugs are tested for Toxicity (is it harmful?), efficacy (does it work?) and dose (how much should be given?). Discovery and development of drugs
Recognise the formulae of the four substances Carbon dioxide is CO₂, water is H₂O, glucose is C₆H₁₂O₆ and oxygen is O₂. Photosynthetic reaction
Explain what a limiting factor is The factor in shortest supply, which stops the rate of photosynthesis increasing; raising it raises the rate. Rate of photosynthesis
Describe the light intensity required practical Put pondweed at different distances from a lamp and count the oxygen bubbles, or measure the volume of oxygen, in a set time. Rate of photosynthesis
State what cellulose is used for Cellulose strengthens the cell wall of plant cells. Uses of glucose from photosynthesis
Name where plants store starch and oils Starch is stored in leaves, roots and tubers such as potatoes; many seeds store oils. Uses of glucose from photosynthesis
Write the anaerobic equations for muscles and yeast In muscles: glucose → lactic acid. In plant cells and yeast: glucose → ethanol + carbon dioxide. Aerobic and anaerobic respiration
Explain why heart and breathing rates increase To supply the muscles with more oxygenated blood for the extra respiration needed to contract. Response to exercise
Give examples of metabolic reactions For example respiration, making starch, glycogen or cellulose from glucose, making lipids and proteins, and making urea. Metabolism
Name the three parts of a control system Receptors, coordination centres and effectors. Homeostasis
Name the parts of the CNS The central nervous system (CNS) is the brain and spinal cord. The human nervous system
Put the reflex arc in order Stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector → response. The human nervous system
Locate the main endocrine glands Pituitary, thyroid, adrenal glands, pancreas, ovaries and testes on a body diagram. Human endocrine system
Match glands to their hormones E.g. pancreas: insulin; testes: testosterone. Human endocrine system
Describe how insulin lowers blood glucose Insulin makes glucose move from the blood into cells; liver and muscle cells store it as glycogen. Control of blood glucose concentration
Define ovulation The release of a mature egg from an ovary, about every 28 days. Hormones in human reproduction
Explain how barrier methods work Condoms and diaphragms stop sperm reaching the egg. Contraception
Define sexual reproduction The joining (fusion) of a male gamete and a female gamete. Sexual and asexual reproduction
State how many gametes meiosis produces The cell divides twice to form four gametes. Meiosis
Describe the structure of DNA simply DNA is a polymer made up of two strands forming a double helix. DNA and the genome
Put nucleus, chromosome and gene in size order Nucleus (largest), then chromosome, then gene (a small section of DNA on a chromosome). DNA and the genome
Use genotype, phenotype, homozygous and heterozygous correctly Genotype is the alleles present, phenotype is the characteristic; homozygous means the same alleles, heterozygous different. Genetic inheritance
State which allele causes each disorder Polydactyly is caused by a dominant allele; cystic fibrosis by a recessive allele. Inherited disorders
Give the sex chromosomes of each sex Females are XX; males are XY. Sex determination
Classify causes of variation Genetic (genes inherited), environmental (conditions of development) or a combination of both. Variation
State when simple life first developed All species evolved from simple life forms that first developed more than three billion years ago. Evolution
Give examples of chosen characteristics Disease resistance in crops, more meat or milk, gentle dogs, large or unusual flowers. Selective breeding
Define genetic engineering Modifying an organism's genome by introducing a gene from another organism to give a desired characteristic. Genetic engineering
Give examples of genetic engineering Bacteria that make human insulin; crops resistant to disease, insects or herbicides; bigger, better fruits. Genetic engineering
Name two types of evidence for evolution The fossil record and the evolution of antibiotic resistance in bacteria. Evidence for evolution
Describe three ways fossils form Parts that have not decayed, parts replaced by minerals, and preserved traces such as footprints. Fossils
List the causes of extinction Environmental change, new predators, new diseases, new competitors and catastrophic events. Extinction
State ways to reduce antibiotic resistance Don't prescribe antibiotics for viral or non-serious infections, complete the course, and restrict their use in farming. Resistant bacteria
Use binomial names An organism's scientific name is its genus followed by its species, e.g. Homo sapiens. Classification of living organisms
List what plants compete for Light and space, and water and mineral ions from the soil. Communities
List what animals compete for Food, mates and territory. Communities
List the abiotic factors in the specification Light intensity, temperature, moisture level, soil pH and mineral content, wind intensity and direction, carbon dioxide (plants) and oxygen (aquatic animals). Abiotic factors
List the four biotic factors in the specification Availability of food, new predators arriving, new pathogens, and one species outcompeting another. Biotic factors
Classify adaptations as structural, behavioural or functional Structural means body features, behavioural means what it does, and functional means processes inside the body. Adaptations
State why food chains start with producers Producers (green plants and algae) make glucose by photosynthesis, so they produce the biomass for the rest of the chain. Levels of organisation
Calculate a mean, median and mode Mean = total ÷ number of values; median = middle value when in order; mode = most common value. Levels of organisation
Name the processes in the water cycle Evaporation, transpiration, condensation, precipitation, and water draining back into rivers and seas. How materials are cycled
Name human activities that reduce biodiversity For example pollution, building, farming, deforestation and destroying peat bogs. Biodiversity
Explain why more waste is produced The human population is growing rapidly and the standard of living is rising, so more resources are used. Waste management
Explain how land use reduces biodiversity Habitats are destroyed, so there is less space, food and shelter for other plants and animals. Land use
Give reasons for tropical deforestation To provide land for cattle and rice fields, and to grow crops for biofuels. Deforestation
Give human activities that increase these gases Burning fossil fuels, deforestation and destroying peat add carbon dioxide; cattle, rice fields and landfill add methane. Global warming
Name compounds from their formulae A metal with a non-metal ends in -ide (NaCl, sodium chloride); -ate means oxygen is also present (CaCO₃, calcium carbonate). Atoms, elements and compounds
Count the atoms in a formula In Ca(OH)₂ the 2 multiplies everything in the brackets: 1 Ca, 2 O and 2 H, so 5 atoms. Atoms, elements and compounds
Match each separation method to its use Filtration, crystallisation, simple distillation, fractional distillation or chromatography, depending on what is in the mixture. Mixtures
Describe filtration and crystallisation Filter off an insoluble solid; evaporate some water from a solution, then cool it so crystals of the dissolved solid form. Mixtures
Describe the plum pudding model The atom is a ball of positive charge with negative electrons embedded in it. The development of the model of the atom
Put the atomic models in order Indivisible spheres → plum pudding → nuclear model → Bohr's shells → protons → neutrons (Chadwick). The development of the model of the atom
Define atomic number The number of protons in an atom; all atoms of the same element have the same number. Relative electrical charges of subatomic particles
Define mass number The total number of protons and neutrons in an atom. Size and mass of atoms
Find protons, neutrons and electrons in atoms Protons = electrons = atomic number; neutrons = mass number − atomic number. Size and mass of atoms
Explain what relative atomic mass means An average value for the atoms of an element that takes account of the abundance of each isotope. Relative atomic mass
Write electronic structures of the first 20 elements Fill the innermost shells first, e.g. sodium (11 electrons) is 2,8,1. Electronic structure
Draw electron shell diagrams Draw circles for the shells around the nucleus and dots or crosses for the electrons. Electronic structure
State how the elements are ordered In order of atomic (proton) number. The periodic table
Describe problems with early tables They were incomplete, and strict atomic weight order put some elements in groups with the wrong properties. Development of the periodic table
Define metals by the ions they form Elements that react to form positive ions are metals; elements that do not are non-metals. Metals and non-metals
Compare physical properties of metals and non-metals Metals are usually shiny, high melting, malleable conductors; non-metals are usually dull, brittle, low melting and poor conductors. Metals and non-metals
State that noble gases are unreactive They are unreactive and do not easily form molecules; they exist as single atoms. Group 0
Describe their reactions with water They float and fizz; sodium melts into a ball; potassium's hydrogen burns with a lilac flame. Group 1
State the reactivity trend down Group 1 Reactivity increases going down the group: lithium, then sodium, then potassium. Group 1
Describe the trends down Group 7 Relative molecular mass, melting point and boiling point increase; reactivity decreases. Group 7
Choose the bond type from the elements Metal + non-metal gives ionic bonding; non-metals only give covalent bonding; metals (elements or alloys) have metallic bonding. Chemical bonds
Name the particles in each type of bond Ionic: oppositely charged ions; covalent: atoms sharing pairs of electrons; metallic: positive ions and delocalised electrons. Chemical bonds
Work out the charge from the group number Group 1 → 1+, Group 2 → 2+, Group 6 → 2−, Group 7 → 1−. Ionic bonding
Name the force holding the ions together Strong electrostatic forces of attraction between oppositely charged ions. Ionic compounds
Recognise small molecules from their formulae Formulae of a few non-metal atoms, e.g. H₂, Cl₂, HCl, H₂O, NH₃, CH₄. Covalent bonding
Describe what delocalised electrons are The outer shell electrons of metal atoms are delocalised: free to move through the whole structure. Metallic bonding
Describe particles in solids, liquids and gases Regular and vibrating in solids, close but moving around in liquids, far apart and moving quickly in gases. The three states of matter
Know that aqueous means dissolved in water Any solution in water, such as sodium chloride solution or dilute hydrochloric acid, is (aq). State symbols
State when ionic compounds conduct electricity When melted (molten) or dissolved in water, but not when solid. Properties of ionic compounds
State that small molecules don't conduct electricity The molecules have no overall electric charge. Properties of small molecules
State that polymers are solids at room temperature The forces between their large molecules are strong enough to keep them solid. Polymers
State that they have very high melting points They are solids at room temperature with very high melting and boiling points. Giant covalent structures
Define an alloy A mixture of a metal with other elements, usually other metals. Properties of metals and alloys
Name the particles that carry the charge Delocalised electrons carry electrical charge through the metal. Metals as conductors
Describe the bonding in diamond Each carbon atom forms four covalent bonds with other carbon atoms. Diamond
State the number of bonds each carbon forms Each carbon atom forms three covalent bonds with three other carbon atoms. Graphite
Describe fullerenes as hollow carbon molecules They are based on hexagonal rings of carbon atoms, sometimes with rings of five or seven atoms. Graphene and fullerenes
Name buckminsterfullerene and give its formula The first fullerene discovered: C₆₀, a hollow, spherical molecule. Graphene and fullerenes
Calculate a missing mass in a reaction Total mass of reactants = total mass of products, so subtract the known masses from the total. Conservation of mass and balanced chemical equations
Calculate M_r of a simple formula Add the A_r of every atom, e.g. CO₂ = 12 + (2 × 16) = 44. Relative formula mass
Explain a mass decrease when gas forms The gas produced escapes into the air, so its mass is no longer measured. Mass changes when a reactant or product is a gas
Find the range of a set of results Range = highest value − lowest value. Chemical measurements
Convert cm³ to dm³ Divide by 1000, e.g. 250 cm³ = 0.250 dm³. Concentration of solutions
Define oxidation and reduction using oxygen Oxidation is the gain of oxygen and reduction is the loss of oxygen. Metal oxides
Describe metal reactions with water and acid Say what you would see, e.g. fizzing, and name the products (metal hydroxide or salt, plus hydrogen). The reactivity series
State which metals carbon can extract Metals below carbon in the reactivity series, such as zinc, iron and copper, can be extracted by heating their oxides with carbon. Extraction of metals and reduction
Name the salt from the acid used Hydrochloric acid gives chlorides and sulfuric acid gives sulfates. Reactions of acids with metals
Describe the test for hydrogen A lit splint held at the mouth of the tube burns the hydrogen with a squeaky pop. Reactions of acids with metals
Predict products of acid with base or alkali acid + metal oxide or metal hydroxide → salt + water. Neutralisation of acids and salt production
Predict products of acid with a carbonate acid + metal carbonate → salt + water + carbon dioxide. Neutralisation of acids and salt production
Describe filtering and crystallising Filter off the excess solid, heat to evaporate some water, then leave the solution to cool and crystallise. Soluble salts
Measure pH with universal indicator Add the indicator and match its colour to a pH colour chart. The pH scale and neutralisation
Define an electrolyte A molten or dissolved ionic compound, which conducts electricity because its ions are free to move. The process of electrolysis
Predict products for any molten binary compound The metal forms at the cathode and the non-metal forms at the anode. Electrolysis of molten ionic compounds
State when electrolysis is used for extraction When the metal is too reactive to be extracted by carbon, or when it reacts with carbon. Using electrolysis to extract metals
State the products from sodium chloride solution Hydrogen forms at the cathode and chlorine at the anode, leaving sodium hydroxide solution. Electrolysis of aqueous solutions
Give examples of endothermic reactions Thermal decomposition and the reaction of citric acid with sodium hydrogencarbonate are endothermic. Energy transfer during exothermic and endothermic reactions
Classify a reaction from temperature data A rise in temperature means the reaction is exothermic; a fall means it is endothermic. Energy transfer during exothermic and endothermic reactions
Label the parts of a reaction profile Identify the reactants, products, activation energy and overall energy change on a given profile. Reaction profiles
Identify exothermic or endothermic from a profile Products lower than reactants means exothermic; products higher than reactants means endothermic. Reaction profiles
Calculate a mean rate of reaction Divide the quantity of reactant used or product formed by the time taken, e.g. 30 cm³ ÷ 20 s = 1.5 cm³/s. Calculating rates of reactions
Give the correct unit for rate Use g/s for a mass or cm³/s for a volume of gas, matching the units of the quantity and the time. Calculating rates of reactions
State how each factor changes the rate Increasing the concentration, pressure, surface area or temperature, or adding a catalyst, increases the rate. Factors which affect the rates of chemical reactions
Define activation energy The minimum amount of energy that particles must have to react. Collision theory and activation energy
Know that enzymes are biological catalysts Enzymes are the catalysts that speed up reactions in living things. Catalysts
Describe what a reversible reaction is The products of the reaction can react to produce the original reactants. Reversible reactions
Know the reverse has the opposite energy change If the forward reaction is exothermic, the reverse reaction is endothermic, and the other way round. Energy changes and reversible reactions
Define a closed system Apparatus that prevents the reactants and products from escaping. Equilibrium
Name the first four alkanes and their formulae Methane CH₄, ethane C₂H₆, propane C₃H₈ and butane C₄H₁₀. Crude oil, hydrocarbons and alkanes
Define a fraction A mixture of hydrocarbons with a similar number of carbon atoms, and so similar boiling points. Fractional distillation and petrochemicals
Recall how properties change with molecule size Bigger molecules: higher boiling point, higher viscosity and lower flammability. Properties of hydrocarbons
Name the two types of product Cracking produces smaller alkanes and another type of hydrocarbon called alkenes. Cracking and alkenes
Describe the bromine water test for alkenes Shake with bromine water: it turns from orange to colourless if an alkene is present. Cracking and alkenes
Contrast everyday and chemical meanings of pure In everyday language 'pure' means nothing has been added (e.g. pure milk), but the product can still be a mixture. Pure substances
Use melting points to spot pure samples A pure substance melts at a specific temperature; a mixture melts over a range of temperatures. Pure substances
Identify formulations from given information Look for a product made by mixing measured amounts of components, each with a purpose. Formulations
Match spots to known reference substances Spots of the same substance travel the same distance on the same paper with the same solvent. Chromatography
Describe the paper chromatography method Pencil start line, small spots, solvent below the line, lid on, mark the solvent front. Chromatography
Tell the hydrogen and oxygen tests apart Hydrogen: burning splint gives a pop. Oxygen: glowing splint relights. Test for hydrogen
Tell the oxygen and hydrogen tests apart Oxygen: glowing splint relights. Hydrogen: burning splint gives a pop. Test for oxygen
Name the chemical in limewater Limewater is an aqueous solution of calcium hydroxide. Test for carbon dioxide
Give a safety precaution for chlorine Chlorine is toxic, so use small amounts in a fume cupboard. Test for chlorine
Name the gases present in small proportions Carbon dioxide, water vapour and noble gases such as argon are present in small proportions. The proportions of different gases in the atmosphere
State how long the proportions have been similar The proportions of the gases have been much the same as today for about 200 million years. The proportions of different gases in the atmosphere
Name the main gas in the early atmosphere It was mainly carbon dioxide with little or no oxygen, like the atmospheres of Mars and Venus today. The Earth's early atmosphere
Describe how the oceans formed Water vapour released by volcanoes condensed to form the oceans. The Earth's early atmosphere
Write the word equation for photosynthesis carbon dioxide + water → glucose + oxygen, with light as the energy source. How oxygen increased
Name rocks and fuels that lock up carbon Sedimentary rocks such as limestone, and the fossil fuels coal, crude oil and natural gas. How carbon dioxide decreased
State why greenhouse gases are needed They keep the Earth's temperature high enough to support life. Greenhouse gases
Give two activities that release methane Farming cattle and other livestock, growing rice in paddy fields, and waste decaying in landfill sites. Human activities which contribute to an increase in greenhouse gases in the atmosphere
Give potential effects of climate change For example, rising sea levels, more frequent and severe storms, and changes in rainfall. Global climate change
Define carbon footprint The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event. The carbon footprint and its reduction
Name the pollutants released by burning fuels Carbon dioxide, water vapour, carbon monoxide, sulfur dioxide, oxides of nitrogen and particulates. Atmospheric pollutants from fuels
Name the gases that cause acid rain Sulfur dioxide and oxides of nitrogen cause acid rain. Properties and effects of atmospheric pollutants
Give effects of acid rain It damages buildings and statues, harms trees and plants, and makes lakes acidic, harming aquatic life. Properties and effects of atmospheric pollutants
Define finite and renewable resources A finite resource is used faster than it forms, so it will run out; a renewable resource is replaced as fast as it is used. Using the Earth's resources and sustainable development
Give natural products replaced by synthetic ones For example, wool and cotton supplemented by synthetic fibres such as polyester, or natural rubber by synthetic rubber. Using the Earth's resources and sustainable development
Explain why potable water is not pure It contains dissolved substances, whereas pure water contains only water molecules. Potable water
List the steps in treating fresh water Choose a suitable source of fresh water, pass it through filter beds, then sterilise it. Potable water
State what sewage treatment must remove Sewage and agricultural waste water need organic matter and harmful microbes removed. Waste water treatment
State what an LCA is used for To assess the environmental impact of a product over its whole life, including transport at each stage. Life cycle assessment
Name materials made from limited raw materials Metals, glass, building materials, clay ceramics and most plastics. Ways of reducing the use of resources
Name the ways energy is transferred Mechanically (a force doing work), electrically (a current doing work), by heating and by radiation such as light. Energy stores and systems
Calculate gravitational potential energy Multiply mass (kg) × gravitational field strength (N/kg) × height (m) to get the energy in joules. Changes in energy
Define specific heat capacity The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C. Energy changes in systems
Define power Power is the rate at which energy is transferred, or the rate at which work is done. Power
Calculate power from energy and time Divide the energy transferred (J) by the time taken (s). Power
Give examples of energy being dissipated Friction heats moving parts, air resistance heats the air, and a motor makes sound. Energy transfers in a system
Calculate efficiency from energy values Divide the useful output energy by the total input energy. Efficiency
Sort resources into renewable and non-renewable Coal, oil, gas and nuclear fuel are non-renewable; all the others are renewable. National and global energy resources
Link energy resources to their uses The three main uses are transport, electricity generation and heating. National and global energy resources
Draw a simple series circuit correctly Use a ruler, straight wires and the correct symbols, with no gaps in the loop. Standard circuit diagram symbols
Recognise diode, LED, fuse and variable resistor Tell apart symbols that look alike, such as the diode and the LED, or the resistor and the fuse. Standard circuit diagram symbols
State what a circuit needs for current A closed circuit (complete loop) that includes a source of potential difference, such as a cell. Electrical charge and current
Calculate charge using Q = I t Multiply the current in amps by the time in seconds to get the charge in coulombs. Electrical charge and current
Describe how resistance affects current For a given potential difference, the greater the resistance, the smaller the current. Current, resistance and potential difference
Calculate pd using V = I R Multiply the current in amps by the resistance in ohms to get the pd in volts. Current, resistance and potential difference
Recall that a thermistor's resistance falls when hot The resistance of a thermistor decreases as temperature increases. Resistors
State the series and parallel rules Series: same current, pd shared. Parallel: same pd across each branch, branch currents add up. Series and parallel circuits
Add resistances in series Use R_total = R₁ + R₂. Series and parallel circuits
Name a source of direct pd Cells and batteries supply a direct potential difference. Direct and alternating potential difference
State the job of each wire Live carries the alternating pd from the supply, neutral completes the circuit, earth is a safety wire. Mains electricity
Explain what power means Power is the rate of energy transfer: the energy transferred each second. Power
Calculate power using P = V I Multiply the pd in volts by the current in amps to get the power in watts. Power
State what affects the energy transferred The power of the appliance and how long it is switched on for. Energy transfers in everyday appliances
Calculate energy using E = P t Power in watts × time in seconds gives energy in joules. Energy transfers in everyday appliances
State what a step-up transformer does It increases the potential difference from the power station to the transmission cables. The National Grid
State what a step-down transformer does It decreases the potential difference to a much lower value for domestic use. The National Grid
Recall and use density = mass ÷ volume Substitute into ρ = m / V with mass in kg and volume in m³ to get a density in kg/m³. Density of materials
State that mass is conserved When a substance changes state the number of particles stays the same, so its mass does not change. Changes of state
Define internal energy The total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system. Internal energy
Define specific heat capacity The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C. Temperature changes in a system and specific heat capacity
Substitute into ΔE = m c Δθ Calculate the change in thermal energy with m in kg, c in J/kg °C and Δθ in °C. Temperature changes in a system and specific heat capacity
Know temperature stays constant during state changes While a substance melts, boils, freezes or condenses, its temperature does not change. Changes of state and specific latent heat
Link gas temperature to molecules' kinetic energy The higher the temperature, the greater the average kinetic energy of the molecules, so the faster they move on average. Particle motion in gases
Give the relative charge of each particle Proton +1, neutron 0, electron −1, so the nucleus is positively charged. The structure of an atom
Recall the size of an atom The radius of an atom is about 1 × 10⁻¹⁰ m. The structure of an atom
State what mass number means The mass number is the total number of protons and neutrons in the nucleus. Mass number, atomic number and isotopes
Explain why atoms have no overall charge An atom has equal numbers of protons and electrons, and their charges are equal and opposite. Mass number, atomic number and isotopes
Describe the plum pudding model The atom is a ball of positive charge with negative electrons embedded in it. The development of the model of the atom
Define radioactive decay and activity Unstable nuclei give out radiation to become more stable; activity is decays per second, in becquerels (Bq). Radioactive decay and nuclear radiation
State what absorbs each radiation Alpha: paper; beta: a few mm of aluminium; gamma: reduced by thick lead or concrete. Radioactive decay and nuclear radiation
Recall the symbols for alpha and beta Alpha is \({}^{4}_{2}\mathrm{He}\) and beta is \({}^{0}_{-1}\mathrm{e}\). Nuclear equations
Define half-life The time for the number of unstable nuclei in a sample, or its count rate, to halve. Half-lives and the random nature of radioactive decay
Define contamination and irradiation Contamination: unwanted radioactive material on or in something; irradiation: exposure to radiation from outside. Radioactive contamination
Sort common quantities into scalars and vectors Distance, speed, mass, time, energy and temperature are scalars; displacement, velocity, acceleration and force are vectors. Scalar and vector quantities
Name examples of non-contact forces Gravitational, electrostatic and magnetic forces act even when the objects are physically separated. Contact and non-contact forces
Calculate weight using W = m g For example, 60 kg × 9.8 N/kg = 588 N. Gravity
Find the resultant of forces along a line Add forces acting in the same direction; subtract forces acting in opposite directions. Resultant forces
Calculate work done using W = F s For example, 50 N × 3.0 m = 150 J. Work done and energy transfer
Distinguish elastic and inelastic deformation An elastically deformed object returns to its original shape when the forces are removed; an inelastically deformed one does not. Forces and elasticity
State that displacement is a vector Displacement is the straight-line distance from the start point to the finish point, with the direction of that line. Distance and displacement
Calculate distance using s = v t For example, 1.5 m/s for 60 s gives 90 m. Speed
Recall typical speeds of everyday motion Walking ~1.5 m/s, running ~3 m/s, cycling ~6 m/s, sound in air ~330 m/s. Speed
Explain the difference between speed and velocity Speed is a scalar (magnitude only); velocity is a vector (magnitude and direction). Velocity
Plot a distance–time graph from data Time on the x-axis, distance on the y-axis, labelled axes with units and sensible scales. The distance–time relationship
Calculate acceleration using a = Δv ÷ t From 4 m/s to 16 m/s in 3 s: a = 12 ÷ 3 = 4 m/s². Acceleration
Describe motion from a velocity–time graph Horizontal line: constant velocity; sloping up: accelerating; sloping down: decelerating. Acceleration
State Newton's First Law If the resultant force on an object is zero, it stays at rest or keeps moving at the same velocity. Newton's First Law
Find a force from steady motion At a steady speed in a straight line, the driving force equals the total resistive force. Newton's First Law
Calculate force using F = m a For example, 1200 kg × 2.5 m/s² = 3000 N. Newton's Second Law
State Newton's Third Law Whenever two objects interact, the forces they exert on each other are equal and opposite. Newton's Third Law
Calculate stopping distance from given data Add the thinking distance and the braking distance. Stopping distance
List factors that increase reaction time Tiredness, drugs, alcohol and distractions (e.g. using a phone). Reaction time
Explain how wet or icy roads affect braking There is less friction between the tyres and the road, so the braking distance is longer. Factors affecting braking distance 1
Describe the energy transfer when a vehicle brakes Energy is transferred from the kinetic store of the vehicle to the thermal store of the brakes. Factors affecting braking distance 2
State what waves transfer Waves transfer energy (and can carry information) from place to place, but they do not transfer matter. Transverse and longitudinal waves
Define frequency and period Frequency is the number of waves passing a point each second (Hz); the period is the time for one wave (s). Properties of waves
Calculate wave speed using v = f λ Multiply the frequency in Hz by the wavelength in m to get the wave speed in m/s. Properties of waves
Link spectrum position to wavelength and frequency Radio waves have the longest wavelength and lowest frequency; gamma rays have the shortest wavelength and highest frequency. Types of electromagnetic waves
State the effects of ultraviolet on skin Ultraviolet can make skin age prematurely and increases the risk of skin cancer. Properties of electromagnetic waves 2
Give two uses of microwaves Satellite communications and cooking food. Uses and applications of electromagnetic waves
Give three uses of infrared Electrical heaters, cooking food and infrared cameras. Uses and applications of electromagnetic waves
Identify magnetic forces as non-contact forces Magnets attract or repel each other without touching, so these are non-contact forces. Poles of a magnet
Draw the field pattern of a bar magnet Curved lines from the north pole to the south pole, with arrows, closest together at the poles. Magnetic fields
Describe how to show a wire's magnetic field Put plotting compasses around a vertical wire: they line up in a circle when the current is switched on. Electromagnetism

Grade 5

Grade 5 checklist (PDF)

Compare prokaryotic and eukaryotic cells Say what both have (cell membrane, cytoplasm, ribosomes) and how they differ, above all whether the DNA is enclosed in a nucleus. Eukaryotes and prokaryotes
Convert between mm, µm and nm Multiply by 1000 for each step down (mm → µm → nm) and divide by 1000 for each step up. Eukaryotes and prokaryotes
Explain why some plant cells lack chloroplasts Cells that receive no light, such as root cells, cannot photosynthesise, so they have no chloroplasts. Animal and plant cells
Describe the adaptations of each specialised cell e.g. a sperm cell has a tail, many mitochondria and enzymes in its head. Cell specialisation
State what cell division does in adults In mature animals, cell division is mainly for repair and replacement. Cell differentiation
Use magnification = image size ÷ real size Rearrange the equation to find the magnification, the image size or the real size. Microscopy
Prepare a slide and focus a microscope Thin sample, stain, coverslip; start on the lowest power and focus with the coarse, then the fine, focus. Microscopy
Put cell, nucleus, chromosome and gene in order Largest to smallest: cell, nucleus, chromosome, gene. Chromosomes
Describe what happens in each stage The cell grows, copies its sub-cellular structures and DNA, divides its nucleus, then splits in two. Mitosis and the cell cycle
State why mitosis is important For the growth and development of multicellular organisms, and to repair and replace cells. Mitosis and the cell cycle
Recognise where mitosis is happening e.g. a root tip growing, a cut healing, an embryo developing. Mitosis and the cell cycle
Compare embryonic and adult stem cells Embryonic stem cells can become most types of human cell; adult bone marrow stem cells form fewer types, including blood cells. Stem cells
Describe uses of meristem cloning Making clones quickly and cheaply, saving rare species, and producing crops with useful features. Stem cells
Explain the factors that affect the rate A bigger concentration gradient, a higher temperature and a larger surface area all increase the rate of diffusion. Diffusion
Describe the osmosis required practical Weigh pieces of plant tissue, leave them in a range of concentrations, then reweigh them. Osmosis
Calculate percentage change in mass Change in mass ÷ starting mass × 100; a loss in mass gives a negative answer. Osmosis
Describe two examples of active transport Mineral ions from the soil into root hair cells; sugar from the gut into the blood. Active transport
Classify a structure by its level For example, a red blood cell is a cell, blood is a tissue, the heart is an organ and the circulatory system is an organ system. Principles of organisation
Recall where each digestive enzyme is made Amylase in the salivary glands, pancreas and small intestine; proteases in the stomach, pancreas and small intestine; lipases in the pancreas and small intestine. The human digestive system
Describe the double circulatory system The right ventricle pumps blood to the lungs and the left ventricle pumps blood around the rest of the body. The heart and blood vessels
Describe the role of the pacemaker A group of cells in the right atrium controls the natural resting heart rate; an artificial pacemaker is an electrical device that corrects an irregular heart rate. The heart and blood vessels
Identify blood cells in a photo or diagram Red blood cells are biconcave discs with no nucleus, white blood cells are larger with a nucleus, and platelets are tiny fragments. Blood
List substances transported by the plasma Carbon dioxide, urea, soluble products of digestion such as glucose and amino acids, hormones and antibodies. Blood
Describe how stents and statins treat CHD A stent holds the coronary artery open; statins lower blood cholesterol, which slows the build-up of fatty material. Coronary heart disease: a non-communicable disease
Describe treatments for faulty valves and heart failure Faulty valves are replaced with biological or mechanical valves; heart failure can be treated with a donor heart (or heart and lungs) or, occasionally, an artificial heart. Coronary heart disease: a non-communicable disease
Give factors other than disease affecting health Diet, stress and life situations can have a big effect on both physical and mental health. Health issues
Describe effects of smoking and alcohol in pregnancy Both can harm the unborn baby, e.g. smoking can cause low birth weight and alcohol can damage the baby's brain development. The effect of lifestyle on some non-communicable diseases
Describe malignant tumours and secondary tumours Malignant tumour cells are cancers: they invade neighbouring tissues and spread in the blood to form secondary tumours. Cancer
Give lifestyle risk factors for cancer For example smoking (lung cancer), obesity (e.g. bowel cancer), too much UV light (skin cancer) and some viral infections (e.g. cervical cancer). Cancer
State the function of each leaf tissue Epidermis covers the leaf, palisade does most photosynthesis, spongy mesophyll lets gases diffuse, xylem carries water and phloem carries sugars. Plant tissues
Describe how root hair cells absorb substances They take up water by osmosis and mineral ions by active transport, helped by their large surface area. Plant organ system
Compare the structure of xylem and phloem Xylem is hollow tubes strengthened by lignin; phloem is tubes of elongated cells with pores in the end walls. Plant organ system
Explain how bacteria and viruses make you ill Both reproduce rapidly in the body; bacteria release toxins that damage tissues, and viruses reproduce inside cells and damage them. Communicable (infectious) diseases
Describe ways to reduce the spread of disease Hygiene, isolating infected individuals, destroying or controlling vectors, and vaccination. Communicable (infectious) diseases
Describe how measles and HIV are controlled Measles: vaccinating young children; HIV: condoms, not sharing needles and antiretroviral drugs. Viral diseases
Describe how each disease is spread Salmonella: bacteria swallowed in food or on food prepared in unhygienic conditions; gonorrhoea: sexual contact. Bacterial diseases
Describe how the spread of each is controlled Vaccinating poultry and hygienic food preparation for Salmonella; antibiotics and condoms for gonorrhoea. Bacterial diseases
Describe how rose black spot is treated Use fungicides and/or remove and destroy the affected leaves. Fungal diseases
Describe how the spread of malaria is controlled Stop mosquitoes breeding, and use mosquito nets to avoid being bitten. Protist diseases
Describe phagocytosis A white blood cell engulfs a pathogen and digests it. Human defence systems
Explain how vaccination prevents illness If the live pathogen enters later, white blood cells quickly make the correct antibodies and destroy it before it causes illness. Vaccination
Explain why specific antibiotics are needed Different antibiotics kill different bacteria, so the antibiotic must match the bacterium causing the disease. Antibiotics and painkillers
Describe preclinical testing The drug is tested in a laboratory on cells, tissues and live animals before any people take it. Discovery and development of drugs
Describe the stages of clinical trials Very low doses are given first to check safety; further trials on patients find the optimum dose. Discovery and development of drugs
Explain why photosynthesis is endothermic Energy is transferred from the environment to the chloroplasts by light, so the reaction takes in energy. Photosynthetic reaction
State where the reactants come from Carbon dioxide diffuses into the leaf from the air through the stomata; water is absorbed by the roots and carried up in the xylem. Photosynthetic reaction
Explain the effect of temperature The rate rises up to an optimum temperature, then falls quickly because the enzymes that control photosynthesis denature. Rate of photosynthesis
Explain a one-factor rate graph Where the line rises the factor on the x-axis is limiting; where it levels off another factor has become limiting. Rate of photosynthesis
Describe how glucose reaches storage organs Sugars made in the leaves are carried in solution in the phloem to where they are used or stored. Uses of glucose from photosynthesis
Describe respiration as a continuous exothermic reaction It happens all the time in living cells and transfers energy to the surroundings, supplying the energy for living processes. Aerobic and anaerobic respiration
Describe fermentation and its uses Anaerobic respiration in yeast makes ethanol and carbon dioxide, which are used to make alcoholic drinks and bread. Aerobic and anaerobic respiration
Explain when muscles respire anaerobically When oxygen cannot be supplied fast enough for aerobic respiration alone, as in vigorous exercise. Response to exercise
Calculate changes from exercise data Work out increases, percentage changes and recovery times from tables and graphs of heart rate or breathing rate. Response to exercise
Name the building blocks of large molecules Carbohydrates are made from sugars, proteins from amino acids, and lipids from glycerol and fatty acids. Metabolism
State how a lipid molecule forms One molecule of glycerol joins with three molecules of fatty acids. Metabolism
Explain why homeostasis is important It keeps conditions at the optimum for enzyme action and all cell functions. Homeostasis
Describe the job of each part Receptors detect stimuli, coordination centres process the information, and effectors (muscles or glands) bring about a response. Homeostasis
Explain why reflex actions are fast They are automatic and do not involve the conscious part of the brain. The human nervous system
Describe the ruler-drop reaction time practical Catch a dropped ruler, record the distance it fell and convert it to a reaction time. The human nervous system
Compare hormonal and nervous control Hormones travel in the blood and are slower but longer-lasting; nerve impulses are fast and short-lived. Human endocrine system
Compare the causes of Type 1 and 2 Type 1: the pancreas does not make enough insulin. Type 2: body cells stop responding to insulin. Control of blood glucose concentration
Describe treatments for each type of diabetes Type 1: insulin injections. Type 2: a carbohydrate-controlled diet and an exercise regime. Control of blood glucose concentration
State the roles of the four cycle hormones FSH matures an egg, LH triggers its release, and oestrogen and progesterone maintain the uterus lining. Hormones in human reproduction
Explain how hormonal methods work The pill inhibits FSH so no eggs mature; progesterone implants stop eggs maturing and being released. Contraception
Describe how IUDs and spermicides work IUDs prevent an embryo implanting or release a hormone; spermicides kill or disable sperm. Contraception
Name the cell division each type uses Gametes are made by meiosis; asexual reproduction involves only mitosis. Sexual and asexual reproduction
Describe what happens in meiosis The genetic information is copied, then the cell divides twice to give four genetically different gametes, each with a single set of chromosomes. Meiosis
Give chromosome numbers in body cells and gametes A human body cell has 46 chromosomes (23 pairs) and a human gamete has 23. Meiosis
Define gene and genome A gene is a small section of DNA on a chromosome; the genome is all of an organism's genetic material. DNA and the genome
Complete a Punnett square Put each parent's gametes on the outside and combine one allele from each in every box. Genetic inheritance
Give cross outcomes as ratios or probabilities For example 3 : 1, or a probability of 0.25, 25%, ¼ or 1 in 4. Genetic inheritance
Explain what a carrier is A heterozygous person with one recessive allele who does not have the disorder but can pass it on. Inherited disorders
State what the other 22 pairs do 22 pairs control characteristics only; one pair carries the genes that determine sex. Sex determination
Draw a genetic cross for sex XX × XY in a Punnett square gives XX, XX, XY, XY. Sex determination
Give examples of each cause Blood group is genetic, a scar is environmental, and body mass depends on both. Variation
State that populations show genetic variation There is usually extensive genetic variation within a population of a species. Variation
List the steps of natural selection Variation, competition, the best suited survive and reproduce, alleles passed on, alleles become more common. Evolution
Describe the steps of selective breeding Choose parents with the characteristic, breed them, select the best offspring, and repeat over many generations. Selective breeding
State what GM crops are Crops whose genes have been modified by genetic engineering; they generally give increased yields. Genetic engineering
Explain why genes support Darwin's theory It has been shown that characteristics are passed on to offspring in genes, which explains how they are inherited. Evidence for evolution
Explain why some remains do not decay One or more of the conditions needed for decay (such as oxygen, warmth or moisture) are absent. Fossils
Give examples of catastrophic events Massive volcanic eruptions or collisions with asteroids. Extinction
Explain why bacteria evolve rapidly They reproduce at a fast rate, so there are many generations in a short time. Resistant bacteria
Describe how Linnaeus classified organisms Into groups depending on their structure and characteristics. Classification of living organisms
Name the three domains Archaea, bacteria and eukaryota. Classification of living organisms
Explain what interdependence means Each species depends on others for food, shelter, pollination or seed dispersal, so removing one species can affect the whole community. Communities
Describe a trend in abiotic data State how one variable changes as the other changes, quoting values from the table or graph. Abiotic factors
Explain the effect of food availability More food means more organisms survive and breed, so the population grows; less food has the opposite effect. Biotic factors
Define an extremophile and give an example An organism that lives in extreme conditions of temperature, pressure or salt concentration, e.g. bacteria in deep sea vents. Adaptations
Describe using quadrats to estimate population size Place quadrats randomly, count the organisms, find the mean per quadrat, then scale up to the whole area. Levels of organisation
Name processes that add or remove carbon dioxide Photosynthesis removes carbon dioxide from the air; respiration and combustion release it. How materials are cycled
Explain why biodiversity matters to humans The future of humans relies on it, e.g. for food, materials, medicines and stable ecosystems. Biodiversity
Explain how pollution reduces biodiversity Pollution kills plants and animals, so fewer species survive in the area. Waste management
State why peat bogs are destroyed Peat is dug up to produce garden compost. Land use
Explain how deforestation reduces biodiversity Forest habitats are destroyed and replaced by grazing land or one crop, so many species are lost. Deforestation
Describe biological consequences of global warming Habitat loss as sea levels rise, changes in distribution and migration, and loss of biodiversity. Global warming
Explain how each programme helps biodiversity Say what the programme does and which species or habitats it protects. Maintaining biodiversity
Write word equations for reactions Reactants on the left, products on the right, joined by an arrow, e.g. magnesium + oxygen → magnesium oxide. Atoms, elements and compounds
Describe simple distillation The solvent boils off, is cooled and condensed in a condenser, and is collected, leaving the dissolved solid behind. Mixtures
Describe fractional distillation Liquids with different boiling points are separated using a fractionating column; the lowest boiling point liquid is collected first. Mixtures
Describe the nuclear model A tiny, positively charged nucleus that contains almost all the mass, with electrons outside it. The development of the model of the atom
Explain why atoms have no overall charge The number of electrons equals the number of protons, so the charges cancel. Relative electrical charges of subatomic particles
Identify an element from its proton number Different elements have different numbers of protons, so the atomic number tells you the element. Relative electrical charges of subatomic particles
Define isotopes Atoms of the same element with different numbers of neutrons: same atomic number, different mass number. Size and mass of atoms
Recall the sizes of atoms and nuclei Atom radius about 0.1 nm (1 × 10⁻¹⁰ m); nucleus radius less than 1/10 000 of that (about 1 × 10⁻¹⁴ m). Size and mass of atoms
Calculate A_r for two isotopes Multiply each mass number by its percentage abundance, add the results, then divide by 100. Relative atomic mass
Explain why A_r is rarely whole It is an average of isotopes with different mass numbers, weighted by how common each one is. Relative atomic mass
Link electronic structure to group and period Outer electrons = group number (Groups 1 to 7); number of occupied shells = period. Electronic structure
Identify an element from its electronic structure Add up the electrons to get the atomic number, e.g. 2,8,5 is 15, which is phosphorus. Electronic structure
Explain why group members react similarly They have the same number of electrons in their outer shell. The periodic table
Link position to electronic structure Group number = outer electrons (Groups 1 to 7); period = number of occupied shells. The periodic table
Describe what Mendeleev did He left gaps for undiscovered elements and changed the order of some elements to fit their properties. Development of the periodic table
Compare the oxides of metals and non-metals Metal oxides are basic; non-metal oxides are usually acidic. Metals and non-metals
Explain their unreactivity using electrons Their atoms have stable arrangements of electrons: a full outer shell of 8 (2 for helium). Group 0
Describe the boiling point trend Boiling points increase going down the group, as relative atomic mass increases. Group 0
Write equations for their reactions With water, oxygen and chlorine, e.g. 2K + 2H₂O → 2KOH + H₂. Group 1
Describe the compounds halogens form Ionic compounds with metals (halide ions, 1−); covalent molecules with non-metals, e.g. HCl. Group 7
Predict whether a displacement reaction happens A more reactive halogen displaces a less reactive one from a solution of its salt. Group 7
Decide the bond type from a formula Use the periodic table to decide whether each element in, for example, KBr, SO₂ or Zn is a metal or a non-metal. Chemical bonds
Write the electronic structure of an ion For example, Na (2,8,1) becomes Na⁺ (2,8) and O (2,6) becomes O²⁻ (2,8). Ionic bonding
Draw dot and cross diagrams for ionic compounds Show each ion in square brackets with its charge, using dots and crosses for electrons from different atoms. Ionic bonding
State that the forces act in all directions Each ion is attracted to all the oppositely charged ions around it, throughout the lattice. Ionic compounds
Recognise an ionic structure from a diagram Look for a regular lattice of two types of ion, often labelled with charges, and no separate molecules. Ionic compounds
Draw dot and cross diagrams for simple molecules Hydrogen, chlorine, hydrogen chloride, water, ammonia and methane, which have single bonds only. Covalent bonding
Describe the metallic bond Strong electrostatic attraction between positive metal ions and the shared delocalised electrons. Metallic bonding
Predict states from melting and boiling points Below the melting point: solid; between the melting and boiling points: liquid; above the boiling point: gas. The three states of matter
Add state symbols to a simple equation For example, Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g). State symbols
Explain high melting points using electrostatic forces A lot of energy is needed to overcome the many strong electrostatic forces between oppositely charged ions. Properties of ionic compounds
Explain low boiling points using intermolecular forces Only weak intermolecular forces must be overcome, which needs little energy. Properties of small molecules
Describe the bonds in a polymer chain The atoms in each chain are linked to each other by strong covalent bonds. Polymers
Recognise a polymer from a diagram Look for a repeating unit in brackets with bonds through the brackets and n after them. Polymers
Explain their very high melting points Many strong covalent bonds must be broken, which needs a lot of energy. Giant covalent structures
Explain why most metals have high melting points Giant structures with strong metallic bonding need a lot of energy to overcome. Properties of metals and alloys
Explain why pure metals are soft The layers of atoms can slide over each other easily. Properties of metals and alloys
Explain electrical conduction in metals The delocalised electrons are free to move through the structure, carrying charge. Metals as conductors
Explain why diamond is very hard Many strong covalent bonds hold the atoms rigidly in a 3D network. Diamond
Explain diamond's very high melting point A lot of energy is needed to break the many strong covalent bonds. Diamond
Explain why graphite is soft and slippery There are no covalent bonds between the layers, so the layers can slide over each other. Graphite
Give uses of fullerenes and nanotubes Fullerenes: drug delivery, lubricants, catalysts; nanotubes: nanotechnology, electronics and strengthening materials. Graphene and fullerenes
Balance a symbol equation Change only the big numbers in front of formulae until every element has the same number of atoms on both sides. Conservation of mass and balanced chemical equations
Calculate M_r for formulae with brackets Multiply everything inside the bracket, e.g. Ca(OH)₂ = 40 + 2 × (16 + 1) = 74. Relative formula mass
Explain why a heated metal gains mass Oxygen atoms from the air combine with the metal, so the metal oxide has a greater mass than the metal. Mass changes when a reactant or product is a gas
Identify an anomalous result A result that clearly does not fit the pattern of the others; leave it out of the mean. Chemical measurements
Calculate concentration in g/dm³ Concentration = mass of solute (g) ÷ volume of solution (dm³). Concentration of solutions
Identify what is oxidised or reduced In an equation, the substance that gains oxygen is oxidised and the substance that loses oxygen is reduced. Metal oxides
Deduce an order of reactivity from results The more vigorous the reaction (more bubbles, bigger temperature rise), the more reactive the metal. The reactivity series
Predict whether a displacement reaction happens A metal displaces another metal from its compound only if it is more reactive. The reactivity series
Write equations for reduction with carbon For example, 2ZnO + C → 2Zn + CO₂. Extraction of metals and reduction
Tell the difference between bases and alkalis A base neutralises an acid; an alkali is a base that dissolves in water, such as a soluble metal hydroxide. Neutralisation of acids and salt production
Explain why excess solid is added Excess solid makes sure all the acid reacts, so the salt solution contains no leftover acid. Soluble salts
Tell when the solid is in excess Solid stays undissolved at the bottom, and for a carbonate the fizzing stops. Soluble salts
Name the ions in acids and alkalis Acids produce H⁺ ions in water and alkalis produce OH⁻ ions in water. The pH scale and neutralisation
Compare universal indicator with a pH probe A pH probe gives a more precise numerical reading; universal indicator gives an approximate value from a colour. The pH scale and neutralisation
Describe the pH change during neutralisation As alkali is added to acid, the pH rises to 7 at neutralisation and above 7 when alkali is in excess. The pH scale and neutralisation
Predict which electrode each ion moves to Positive ions move to the cathode and negative ions move to the anode. The process of electrolysis
Describe what is seen at each electrode For lead bromide, silvery lead forms at the cathode and brown bromine vapour at the anode. Electrolysis of molten ionic compounds
Name the products from aluminium oxide Aluminium forms at the cathode and oxygen forms at the anode. Using electrolysis to extract metals
Explain why electrolysis is expensive Large amounts of energy are needed to melt the compound and to produce the electric current. Using electrolysis to extract metals
Predict the product at the cathode Hydrogen forms if the metal is more reactive than hydrogen; otherwise the metal forms. Electrolysis of aqueous solutions
Predict the product at the anode The halogen forms if halide ions are present; otherwise oxygen forms. Electrolysis of aqueous solutions
Explain energy conservation in a reaction Energy is not created or destroyed, so in an exothermic reaction the products have less energy than the reactants by the amount transferred. Energy transfer during exothermic and endothermic reactions
Read energy values from a profile Activation energy = peak − reactants; overall energy change = products − reactants. Reaction profiles
Interpret graphs of product formed against time The steeper the curve, the faster the rate; a horizontal line means the reaction has stopped. Calculating rates of reactions
Describe the gas-volume method for rates Measure the volume of gas given off at regular time intervals with a gas syringe or an upturned measuring cylinder. Factors which affect the rates of chemical reactions
Describe the disappearing-cross (turbidity) method Time how long it takes for a cross under the flask to disappear as a cloudy precipitate forms. Factors which affect the rates of chemical reactions
Explain concentration and pressure effects There are more particles in the same volume, so collisions are more frequent. Collision theory and activation energy
Explain the effect of surface area More particles of the solid are exposed to the other reactant, so collisions are more frequent. Collision theory and activation energy
Identify a catalyst from experimental data It speeds up the reaction, has the same mass at the end and is not in the equation. Catalysts
Describe heating and cooling ammonium chloride Heating decomposes it into ammonia and hydrogen chloride; cooling makes these gases re-form the white solid. Reversible reactions
Write equations for reversible reactions Use ⇌ in word and balanced symbol equations, e.g. NH₄Cl ⇌ NH₃ + HCl. Reversible reactions
State that equal energy is transferred each way The energy taken in one way is exactly the same as the energy given out the other way. Energy changes and reversible reactions
Describe the copper sulfate reversible reaction Heating blue hydrated copper sulfate gives white anhydrous copper sulfate and water; adding water reverses it. Energy changes and reversible reactions
State when equilibrium is reached When the forward and reverse reactions happen at exactly the same rate. Equilibrium
Know that amounts stay constant at equilibrium The concentrations of reactants and products stop changing, but they are not necessarily equal. Equilibrium
Use the general formula of the alkanes Recognise an alkane from its formula, and write the formula for any number of carbon atoms: 10 carbon atoms gives C₁₀H₂₂. Crude oil, hydrocarbons and alkanes
Draw the displayed formula of an alkane Show every atom and every bond: each carbon atom forms four single bonds and each hydrogen atom forms one. Crude oil, hydrocarbons and alkanes
Describe the temperature gradient in the column The fractionating column is hottest at the bottom and coolest at the top. Fractional distillation and petrochemicals
Explain what feedstock means A raw material used to make other chemicals; fractions are feedstock for the petrochemical industry. Fractional distillation and petrochemicals
Choose a suitable fuel using property data For example, a fuel for a gas stove must have a boiling point below room temperature and be very flammable. Properties of hydrocarbons
State what happens to the fuel in combustion The carbon and hydrogen in the fuel are oxidised, and energy is released. Properties of hydrocarbons
Describe the conditions for catalytic and steam cracking Catalytic: vapour passed over a hot catalyst. Steam: vapour mixed with steam and heated to a very high temperature. Cracking and alkenes
Give uses of the products of cracking Smaller alkanes are used as fuels such as petrol; alkenes are used to make polymers and many other chemicals. Cracking and alkenes
Describe how impurities change melting and boiling Impurities lower the melting point and widen the melting range; dissolved impurities raise the boiling point. Pure substances
Interpret heating curves to judge purity A flat section at a fixed temperature shows a pure substance changing state; a sloping section shows a mixture. Pure substances
Explain why quantities are carefully measured The right amount of each component gives the product the properties it needs. Formulations
Suggest the purpose of a component Use the information given, e.g. a pigment gives colour and a sweetener improves taste. Formulations
Calculate an Rf value Rf = distance moved by substance ÷ distance moved by solvent, both measured from the start line. Chromatography
Name reactions that produce hydrogen Metals with acids, very reactive metals with water, and electrolysis of many solutions (at the negative electrode). Test for hydrogen
Name reactions that produce oxygen Decomposition of hydrogen peroxide, electrolysis (at the positive electrode) and photosynthesis. Test for oxygen
Describe how to test gas from a reaction Use a delivery tube to bubble the gas from the reaction through limewater. Test for carbon dioxide
Name reactions that produce carbon dioxide Acids with metal carbonates, and complete combustion of fuels that contain carbon. Test for carbon dioxide
Name a reaction that produces chlorine Electrolysis of a chloride solution, such as sodium chloride solution: chlorine forms at the positive electrode. Test for chlorine
Calculate the volume of a gas in air Multiply the total volume by the percentage divided by 100, e.g. 20 ÷ 100 × 500 cm³ = 100 cm³ of oxygen. The proportions of different gases in the atmosphere
Name other gases in the early atmosphere Nitrogen from volcanoes gradually built up, and there may have been small proportions of methane and ammonia. The Earth's early atmosphere
State when algae first produced oxygen Algae first produced oxygen about 2.7 billion years ago, and oxygen appeared in the atmosphere soon after. How oxygen increased
Describe how limestone formed Shells and skeletons of sea creatures, made of calcium carbonate, settled, were buried and were compressed into rock. How carbon dioxide decreased
Describe how coal formed Remains of plants, mainly trees, were buried and compressed over millions of years. How carbon dioxide decreased
Describe what happens to the Sun's radiation Short wavelength radiation from the Sun passes through the atmosphere and is absorbed by the Earth's surface, warming it. Greenhouse gases
Explain how deforestation increases carbon dioxide Burning the trees releases carbon dioxide, and fewer trees are left to remove it by photosynthesis. Human activities which contribute to an increase in greenhouse gases in the atmosphere
Describe four different potential effects Give four clearly different effects, each with a short consequence, e.g. sea levels rise, causing flooding. Global climate change
Describe actions to reduce emissions Alternative energy, energy conservation, carbon capture and storage, carbon taxes and licences, carbon off-setting and carbon neutrality. The carbon footprint and its reduction
Describe how carbon monoxide and soot form Incomplete combustion in a limited supply of oxygen produces carbon monoxide and carbon particles (soot). Atmospheric pollutants from fuels
Describe how sulfur dioxide forms Sulfur in the fuel reacts with oxygen when the fuel burns. Atmospheric pollutants from fuels
Explain why carbon monoxide is hard to detect It is colourless and odourless, so you cannot see or smell it. Properties and effects of atmospheric pollutants
Define sustainable development Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs. Using the Earth's resources and sustainable development
Give reasons for each treatment step Filter beds remove solid particles; sterilising with chlorine, ozone or ultraviolet light kills microbes. Potable water
Name two methods of desalination Distillation, and processes that use membranes such as reverse osmosis. Potable water
List the stages of sewage treatment in order Screening and grit removal, sedimentation, anaerobic digestion of the sludge, and aerobic biological treatment of the effluent. Waste water treatment
Compare plastic and paper bags using an LCA Plastic bags come from crude oil (finite) but can be reused many times; paper bags come from trees but are reused less. Life cycle assessment
Describe how glass and metals are recycled Glass is crushed and melted to make different glass products; metals are melted and recast or reformed. Ways of reducing the use of resources
Explain why recycling saves resources and energy Less of a limited raw material is used, and usually less energy than extracting and processing new material. Ways of reducing the use of resources
Describe energy changes in common situations Say which store decreases and which increases, e.g. a braking car: kinetic store down, thermal store of the brakes up. Energy stores and systems
Calculate kinetic energy Square the speed first, then multiply by the mass and by 0.5. Changes in energy
Calculate elastic potential energy of a spring Use E_e = ½ k e² with the extension in metres, as long as the limit of proportionality is not exceeded. Changes in energy
Calculate energy using ΔE = m c Δθ Find the temperature change first, then multiply mass × specific heat capacity × temperature change. Energy changes in systems
Compare the power of two machines If two motors do the same work, the one that takes less time has the greater power. Power
Explain how lubrication reduces wasted energy Oil reduces friction between moving parts, so less energy is dissipated by heating. Energy transfers in a system
Explain how insulation reduces energy transfer Thermal insulation lowers the rate of energy transfer by heating, e.g. loft insulation in a house. Energy transfers in a system
Give efficiency as a decimal or percentage Multiply the decimal by 100 to get a percentage; efficiency is never more than 1 (100%). Efficiency
Calculate efficiency from power values Divide the useful power output by the total power input. Efficiency
Explain why some resources are more reliable Wind, solar and waves depend on the weather (and solar on the time of day); fossil fuels and nuclear do not. National and global energy resources
Recognise thermistor and LDR symbols Both start from the resistor box: the thermistor has a line with a flat tail through it, the LDR has two arrows pointing in. Standard circuit diagram symbols
Place ammeters and voltmeters correctly Draw an ammeter in series with a component and a voltmeter in parallel across it. Standard circuit diagram symbols
State that current is the same around a loop In a single closed loop the current has the same value at every point. Electrical charge and current
Rearrange V = I R for I or R Use I = V ÷ R and R = V ÷ I, converting kΩ and mA first. Current, resistance and potential difference
Identify an ohmic conductor from its graph At constant temperature, current is directly proportional to pd, so the I–V graph is a straight line through the origin. Resistors
Describe how a diode controls current Current flows in one direction only; the diode has a very high resistance in the reverse direction. Resistors
Find a missing current or pd e.g. the supply pd equals the sum of the pds in series; the total current equals the sum of the branch currents. Series and parallel circuits
Explain the difference between dc and ac A direct pd acts in one direction only; an alternating pd keeps reversing direction. Direct and alternating potential difference
State the potential of each wire Live is about 230 V (compared with earth); neutral is at or close to 0 V; earth is at 0 V. Mains electricity
Rearrange P = V I Use I = P ÷ V, e.g. to find the current an appliance takes from the mains. Power
Calculate energy using E = Q V Charge in coulombs × pd in volts gives energy in joules. Energy transfers in everyday appliances
Rearrange the density equation Use m = ρ × V to find a mass and V = m ÷ ρ to find a volume. Density of materials
Describe the density required practical Measure mass on a balance and find volume from measured dimensions or by displacement of water. Density of materials
Describe particle changes during melting and boiling Describe how the arrangement, spacing and motion of the particles change. Changes of state
Explain why a change of state is physical No new substance is made: if the change is reversed, the material recovers its original properties. Changes of state
State the two possible effects of heating Heating either raises the temperature of the system or produces a change of state. Internal energy
Link temperature to the particles' kinetic energy A higher temperature means the particles have a higher average kinetic energy: they move or vibrate faster. Internal energy
Work out the temperature change Δθ Δθ is the difference between the final and starting temperatures, not the final temperature. Temperature changes in a system and specific heat capacity
Define specific latent heat The amount of energy needed to change the state of 1 kg of a substance with no change in temperature. Changes of state and specific latent heat
Use E = m L Calculate the energy for a change of state with E in J, m in kg and L in J/kg. Changes of state and specific latent heat
Find changes of state on heating graphs Flat sections show a change of state at the melting or boiling point; sloping sections show a temperature change. Changes of state and specific latent heat
Explain how a gas exerts pressure Molecules collide with the walls of the container and exert a force on them; the force on each unit area is the pressure. Particle motion in gases
Compare the sizes of atom and nucleus The nucleus has a radius less than 1/10 000 of the atom's radius, yet contains almost all of its mass. The structure of an atom
Work out protons, neutrons and electrons Protons = atomic number; neutrons = mass number − atomic number; electrons = protons in a neutral atom. Mass number, atomic number and isotopes
Describe the nuclear model A tiny, positively charged nucleus containing most of the mass, with electrons around it. The development of the model of the atom
Compare plum pudding and nuclear models Charge and mass spread out, compared with concentrated in a nucleus with empty space around it. The development of the model of the atom
Describe what each radiation is Alpha: 2 protons and 2 neutrons; beta: a fast electron from the nucleus; gamma: electromagnetic radiation. Radioactive decay and nuclear radiation
State how alpha decay changes a nucleus The mass number falls by 4 and the atomic number falls by 2. Nuclear equations
State how beta decay changes a nucleus The mass number stays the same and the atomic number goes up by 1. Nuclear equations
Explain why gamma emission changes neither number Gamma is electromagnetic radiation with no mass and no charge. Nuclear equations
Explain what random decay means You cannot predict which nucleus will decay or when, but a large sample decays in a predictable way. Half-lives and the random nature of radioactive decay
Find a half-life from a graph Read the time for the activity or count rate to fall to half of any starting value. Half-lives and the random nature of radioactive decay
State that irradiation does not cause radioactivity An irradiated object does not become radioactive. Radioactive contamination
Represent a vector with an arrow The length of the arrow shows the magnitude and the way it points shows the direction. Scalar and vector quantities
Identify the forces acting in a situation For example, a book on a table has its weight acting down and a normal contact force acting up. Contact and non-contact forces
Show forces as vector arrows Draw each arrow from the object, in the direction of the force, with its length showing the size. Contact and non-contact forces
Find mass or g from a weight m = W ÷ g and g = W ÷ m. Gravity
Describe how to measure weight Hang the object from a calibrated spring-balance (a newtonmeter). Gravity
Recognise balanced forces (zero resultant) If the resultant force is zero, the object stays at rest or keeps moving at a steady velocity. Resultant forces
Find force or distance from work done F = W ÷ s and s = W ÷ F. Work done and energy transfer
Convert between joules and newton-metres 1 J = 1 N m, so 250 N m of work is 250 J. Work done and energy transfer
Calculate force or extension with F = ke For example, k = 40 N/m and e = 0.15 m give F = 6.0 N. Forces and elasticity
Describe the spring extension required practical Hang known weights on a spring, measure its length each time, calculate the extension and plot force against extension. Forces and elasticity
Calculate distance and displacement along a line 40 m east then 15 m west: distance 55 m, displacement 25 m east. Distance and displacement
Explain why displacement can be zero After a round trip back to the start, the displacement is zero although the distance travelled is not. Distance and displacement
Find speed or time using s = vt v = s ÷ t and t = s ÷ v. Speed
Calculate average speed for a whole journey Average speed = total distance ÷ total time. Speed
Use + and − signs for velocity Along a line, e.g. +4 m/s to the right and −4 m/s to the left. Velocity
Calculate speed from the gradient Speed = change in distance ÷ change in time for a straight section. The distance–time relationship
Find acceleration from a velocity–time graph Acceleration = gradient = change in velocity ÷ time taken. Acceleration
Explain steady motion using balanced forces A zero resultant force means there is no change in speed or direction. Newton's First Law
Find mass or acceleration using F = ma a = F ÷ m and m = F ÷ a. Newton's Second Law
Describe how acceleration depends on force and mass Acceleration is proportional to the resultant force and inversely proportional to the mass. Newton's Second Law
Identify Third Law partner forces If a boy pushes a wall with 150 N, the wall pushes the boy with 150 N in the opposite direction. Newton's Third Law
Calculate thinking distance using s = v t Thinking distance = speed × reaction time. Stopping distance
Calculate thinking distance from reaction time Thinking distance = speed × reaction time. Reaction time
Describe the ruler-drop reaction time test Catch a dropped ruler; the further it falls before you catch it, the longer your reaction time. Reaction time
Explain the effects of worn tyres and brakes Worn tyres grip the road less; worn brakes produce a smaller friction force. Factors affecting braking distance 1
Calculate the work done by a braking force W = F s, where s is the braking distance. Factors affecting braking distance 2
Link braking force to deceleration The greater the braking force, the greater the deceleration (F = m a). Factors affecting braking distance 2
Describe how transverse and longitudinal waves differ Compare the direction of the oscillations with the direction of energy transfer: perpendicular for transverse, parallel for longitudinal. Transverse and longitudinal waves
Identify compressions and rarefactions In a longitudinal wave, compressions are where the particles are close together and rarefactions are where they are spread out. Transverse and longitudinal waves
Use T = 1/f Find the period from the frequency, or the frequency from the period, e.g. f = 50 Hz gives T = 1 ÷ 50 = 0.02 s. Properties of waves
State that all EM waves travel equally fast All EM waves travel at the same speed through a vacuum (space) or air: 3.0 × 10⁸ m/s. Types of electromagnetic waves
Give examples of EM waves transferring energy E.g. infrared from a fire warming your skin, or microwaves heating food in an oven. Types of electromagnetic waves
Draw a ray diagram for refraction Draw the normal; a ray that slows down (e.g. air into glass) bends towards the normal. Properties of electromagnetic waves 1
State which surfaces emit and absorb infrared best Matt black surfaces are the best emitters and absorbers of infrared; shiny silver surfaces are the worst. Properties of electromagnetic waves 1
State the effects of X-rays and gamma rays They are ionising radiation and can cause mutation of genes and cancer. Properties of electromagnetic waves 2
State where gamma rays come from Gamma rays come from changes in the nucleus of an atom. Properties of electromagnetic waves 2
Give uses of visible light and ultraviolet Visible light: fibre optic communications. Ultraviolet: energy-efficient lamps and sun tanning. Uses and applications of electromagnetic waves
Describe the difference between permanent and induced magnets A permanent magnet produces its own magnetic field; an induced magnet only becomes a magnet when it is placed in a magnetic field. Poles of a magnet
Plot a magnetic field using a compass Mark where the compass needle points, move the compass on, repeat, then join the dots from N to S. Magnetic fields
State how field strength depends on distance The field is strongest at the poles and gets weaker further from the magnet. Magnetic fields
Draw the field around a straight wire Circles centred on the wire, further apart further out, with arrows showing the direction. Electromagnetism
State what affects the strength of the field The field is stronger for a bigger current, and weaker further from the wire. Electromagnetism

Stuck? Get 1-to-1 help. Chhetri Academy tutors GCSE and A level Maths and Science online, with a free 30-minute trial lesson.

Book a free trial