Lesson plan

Gas pressure

Increase the pressure of a gas to make popcorn and set off a rocket.
Science content
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Atoms, Molecules (3-7)
Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6)
Physics: Energy forms, Conservation of Energy (1, 3, 4, 5)
Activities in this lesson
  • balloon
  • all materials in activities

Introduction to gas pressure:
The air is made of gas. Many many tiny particles, too small to see, bumping each other and the walls.
If we squeeze some gas particles into a balloon, they are still bumping around, but as there are more of them, they bump the sides of the balloon, and push against it - that is pressure - the pushing. If we blow the balloon up too much, the pressure is too much for the balloon and it bursts.

The pressure also makes popcorn pop.
Make popcorn (or start earlier if it takes a while).
Optional: draw popped and un-popped kernels.
Show slow-motion popcorn-popping video to each table, and check drawings.
Ask students why the popcorn pops - prompt if needed that popcorn contains water that is heated to a gas... which expands... and puts pressure on the husk of the kernal... until it pops.

We will now use gas pressure to make a toy.
Show how to make a stomp rocket.
Draw your rocket and launcher, showing with arrows and words where the gas pressure is created, and where it travels to shoot the rocket.
Optional: add fins decorate rocket.


Add bottle rocket if time for a powerful rocket demonstration.

Pressure also demonstrated in film canister rocket and baking soda/vinegar rocket demonstration, which use a chemical reaction to generate gas pressure.

Grades taught
Gr 1
Gr 2
Gr 3
Gr 4