Tea Bag Rocket

An easy and fun way to learn about convection currents!

Suitable for kids aged 7+

You Need:
  • Teabag with a string and label
  • Non-flammable plate
  • Scissors Lighter or match
  • Lighter or match

What to do:
Remember - always ask an adult for help with matches and don't do this experiment near any flammable materials.
  1. Remove the staple, label and string from the teabag.
  2. Pour the tea into a bin.
  3. Unfold the teabag.
  4. Turn the teabag into a cylinder - make sure there's a space in the centre. You can use your finger if that helps.
  5. Stand the cylinder on one end on a plate. Make sure it's on a flat surface.
  6. Use a lighter or match to set the top of the teabag cylinder on fire.
  7. What happens? You should see the ashes of the teabag fly into the air!

Why is it so?

Lighting the top of the teabag cylinder heats the air inside the cylinder. The air molecules start to move more quickly and spread out to take up more space, as they have gained more energy. As the air molecules spread out, the air inside the cylinder becomes less dense. Warm, less dense air rises. The ash of the teabag is light and doesn't require much force to lift it. As the warm, less dense air rises, it has enough force to lift the ash of the teabag.

Did you know that hot air balloons use a similar principle.The burner beneath the balloon heats the air inside the balloon. The less dense, heated air in the balloon rises above the denser, cooler air around the balloon and the balloon flies.

Do more cool experiments with the science kits available on this website.