Practise Atmospheric pressure. 11 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Calculate the force exerted by the atmosphere on one side of the window. Use the equation: pressure = force normal to a surface ÷ area of that surface
1.2 × 105 N
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) What causes atmospheric pressure? Tick (✓) one box.[1]
Air molecules colliding with surfaces
Clouds pressing down on the ground
The Earth’s magnetic field
The Sun heating the air
(b) How does the density of the atmosphere change as altitude (height above sea level) increases?[1]
(c) Atmospheric pressure at the top of a mountain is lower than at the bottom of the mountain. Explain why.[2]
Show the answer and mark scheme
(a)Answer: Air molecules colliding with surfaces
(b)Answer: It decreases.
it decreases
(c)Answer: There is less air (a smaller weight of air) above the summit, and the thinner air gives fewer collisions per second with a surface.
there is less air above the top of the mountain / the weight of air above is smaller
(the air is less dense so) fewer air molecules collide with a surface each second
Question 2Medium4 marks
A person can drink through a straw by sucking air out of the straw.
(a) Explain, in terms of pressure, why a person can drink through a straw.[3]
(b) Explain why a straw would not work in this way on the surface of the Moon, which has no atmosphere.[1]
Show the answer and mark scheme
(a)Answer: Sucking lowers the pressure inside the straw; atmospheric pressure on the drink's surface is then greater, and pushes the drink up the straw.
sucking removes air from the straw (and mouth), reducing the pressure inside the straw below atmospheric pressure
atmospheric pressure, acting on the surface of the drink, is now greater than the reduced pressure inside the straw
this pressure difference pushes the drink up the straw and into the mouth
(b)Answer: There is no atmospheric pressure on the Moon to push the drink up.
there is no atmospheric pressure on the Moon to push the drink up the straw
Question 3Hard7 marks
Atmospheric pressure at sea level is 101 kPa. The density of air at sea level is 1.2 kg/m3. A simple model assumes that the atmosphere has the same density at all heights up to a sharp top edge. gravitational field strength = 9.8 N/kg
(a) Use the model to calculate the height of the atmosphere. Use the Physics Equations Sheet.[3]
(b) The radius of the Earth is 6400 km. Calculate the height of the atmosphere in the model as a percentage of the radius of the Earth.[2]
(c) The real atmosphere extends to a much greater height than the model suggests. Explain why.[2]
Show the answer and mark scheme
(a)Answer: 8600 m (8590 m) m
101 kPa = 101 000 Pa
101 000 = h × 1.2 × 9.8
h = 8600 (m)
(b)Answer: 0.13%
(8.59 ÷ 6400) × 100
0.13 (%)
(c)Answer: Air gets less dense with height, so a taller column is needed to give the same weight per square metre.
the density of air decreases with altitude
so a greater height of (less dense) air is needed to give the same weight above each square metre / the same pressure at sea level