Atmospheric Pressure
Atmospheric pressure is the pressure exerted by the weight of the air above us, which decreases with altitude.
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Atmospheric pressure is the pressure exerted by the weight of the air above us, which decreases with altitude.
- Sea level pressure is about 100 kPa
- A barometer measures it
- Pressure falls as you climb a mountain
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Atmospheric Pressure?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Atmospheric Pressure. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Atmospheric Pressure in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Atmospheric Pressure explains how the physical world behaves, from sport and transport to electricity and medicine.
Atmospheric Pressure in detail
Atmospheric pressure is caused by the weight of the air above us pressing on surfaces. At sea level it is about 101,000 Pa (1 atmosphere), and it decreases with altitude because there is less air above. A barometer measures it, historically using a column of mercury about 760 mm high.
Changes in atmospheric pressure are linked to weather: low pressure brings clouds and rain, high pressure is usually dry. Atmospheric pressure makes suction cups and drinking straws work, and explains why the Magdeburg hemispheres were so hard to pull apart once the air had been removed.
How the interactive helps you understand Atmospheric Pressure
Watch the gas particle model in the interactive. Use any sliders or buttons it offers to change the values and see how the gas particle model responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Atmospheric Pressure.
Real-life uses and examples
- Explain everyday devices, such as brakes, lifts or chargers, using Atmospheric Pressure.
- Use Atmospheric Pressure to make sense of a practical and its results.
- Answer “explain” questions by linking Atmospheric Pressure to a clear cause and effect.
Common mistakes to avoid
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Mixing up Atmospheric Pressure with a related quantity that has different units.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Atmospheric Pressure
What is Atmospheric Pressure?
Atmospheric pressure is the pressure exerted by the weight of the air above us, which decreases with altitude.
What are the most important points about Atmospheric Pressure?
The main points are: Sea level pressure is about 100 kPa; A barometer measures it; Pressure falls as you climb a mountain.
Why is Atmospheric Pressure useful?
Understanding Atmospheric Pressure explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Atmospheric Pressure?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Atmospheric Pressure?
Related topics in Physics include Kinetic Energy, Energy Efficiency, Simple Machines.