Teabag Rocket

10, 9, 8, 7, 6, 5, 4, 3, 2, 1... We have lift-off! Create a ‘rocket’ using an empty teabag and a flame. Learn about density of air and how it is affected by change in temperature.

Australian Curriculum links

  • Science > Physical Sciences > Year 3 > ACSSU049
  • Science > Physical Sciences > Year 4 > ACSSU076

You'll need

  • teabag
  • non-flammable plate
  • scissors
  • lighter or match

Try this

Safety: This experiment requires adult supervision. Perform this experiment away from curtains or other flammable materials.

  1. Remove the staple, label and string from the teabag.
  2. Pour out the tea.
  3. Unfold the teabag and stretch it out.
  4. Use your finger to turn the teabag into a cylinder.
  5. Stand the cylinder on one of its end on a plate on a flat surface.
  6. Use a lighter or match to ignite the top of the tea bag cylinder.
  7. Wait a few seconds.
  8. Watch the rocket fly into the air!

Further investigation

How high does your teabag rocket fly? Do larger teabags work better?

What's happening?

The flame created by burning the teabag heated the air inside the teabag cylinder. When the air was heated energy was transferred to individual pieces of air called air molecules. The air molecules moved around more quickly and spread out to take up more space. This means that the air molecules were further apart from each other and therefore the air was less dense. The warmer, less dense air rose above the cooler, denser air.

When the teabag burned, the teabag turned into ash and smoke. The smoke lifted away and all that was left was the ash. Ash is light, so it doesn’t require much force to lift it. The rising of the less dense (heated) air inside the teabag had enough force to lift the ash of the teabag.

Real world links

Hot air balloons work in a similar way. Hot air balloons have a burner beneath a balloon envelope. The burner uses propane to heat the air inside the balloon envelope. As the air inside the balloon envelope is heated, the air inside the balloon envelope becomes less dense. As a result, the less dense (heated) air in the balloon envelope rises above the denser (cooler) air surrounding the balloon.