What you need:
- Empty bottle
- Pen lid
- What to do
What to do:
- Place the bottle on its side and place the pen lid half inside the neck of the bottle. Make sure the hole in the lid is facing the inside of the bottle.
- Challenge a friend to blow the pen lid into the bottle using only their breath.
- Watch as your friend fails to complete the challenge!
The ‘empty’ bottle is actually full of air. By blowing on the pen lid, your breath pushes on the pen lid and the air inside the bottle pushes back. If your friend blows hard enough, their breath will be deflected around the pen lid and some air will flow back out of the bottle, pushing out the lid.
Although we can’t see it, air is all around us and we make use of it every day: we breathe it, we pump it through a vacuum cleaner to clean up dirt, we rely on air pressure to keep car tyres inflated, moving air can be used to generate electricity, and aeroplanes rely on air to stay up in the sky.