Gas pressure and the particle model
Air feels like nothing, yet it presses on every surface with about 100,000 newtons per square metre. The particle model explains exactly why.
Part of your national curriculum
- Chemistry: the particulate nature of matter: Understand the properties of the different states of matter in terms of the particle model, including gas pressure
Lesson overview
What you'll learn in this lesson
Understand the properties of the different states of matter in terms of the particle model, including gas pressure
Key learning points
- • Three states, one model
- • Where pressure comes from
- • Everyday consequences
This lesson at a glance
- 25 minutes
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
Gas pressure and the particle model
Air feels like nothing, yet it presses on every surface with about 100,000 newtons per square metre. The particle model explains exactly why.
In a nutshell
Understand the properties of the different states of matter in terms of the particle model, including gas pressure
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Three states, one model
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
Three states, one model
In a solid, particles vibrate in fixed positions, so shape and volume are fixed. In a liquid, particles touch but slide past one another, so the shape changes but volume does not. In a gas, particles are far apart and move fast in all directions, so a gas fills its container.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 20
Learn
Where pressure comes from
Gas pressure is the total effect of countless particle collisions with a surface. More particles in the same space means more collisions per second and higher pressure. Heating a fixed volume of gas makes particles move faster, so each collision is harder and pressure rises.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · Everyday consequences
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
Everyday consequences
A bicycle tyre gets harder as more air is pumped in; a sealed can bulges when heated; a plastic bottle taken up a mountain and sealed crumples on the way down as outside pressure rises again.
Quick check
Part 11 of 20
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 13 of 20
Explore the idea
Part 14 of 20
Worked example
Worked example: a sealed syringe
The nozzle of a syringe is blocked and the plunger is pushed halfway in. Explanation: the same number of particles now occupies a smaller volume, so collisions with the walls happen more often and pressure rises. The plunger springs back because that raised pressure pushes outwards.
Challenge round
Part 15 of 20
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 17 of 20
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Gas pressure is the total effect of countless ____ collisions with a surface.
More particles in the same space means more collisions per second and higher ____.
Challenge round
Part 18 of 20
Game · Recall cards
Which statement about particles in a gas is correct?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: Gas pressure and the particle model
4 questions, marked with the reasoning shown. No timer.
1. Which statement about particles in a gas is correct?
2. Why can gases be compressed easily but solids cannot?
3. What causes gas pressure?
4. What happens to gas pressure in a sealed container if you heat the gas?
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
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Ask LunaPart 1 of 20 · Watch & discover
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Understand the properties of the different states of matter in terms of the particle model, including gas pressure