S3.5.5 For the adult
Gas pressure
Why does a bicycle tyre go hard when I pump air into it?
What this chapter teaches
A gas pushes on the walls of its container because its particles keep hitting them. More particles, a smaller space, or a hotter gas all mean more or harder hits, so more pressure.
Three questions to ask
There is no one right wording. Listen for the idea.
- Why does a bicycle tyre feel hard when it is pumped up?
- Why do you think a football feels harder on a hot day?
- Does a gas push only down, or in every direction? How could you test it with a balloon?
After the chapter, the learner can
- Explain gas pressure as particles hitting the walls of a container
- Explain why a ball or a tyre feels harder on a hot day
What they copy into their notebook
Gas pressure is the push of particles hitting the walls. Faster particles, more particles, or a smaller volume give more hits, so more pressure.