Here’s what to do”
- Place a balloon inside a 500 ml pop bottle.
- Stretch the balloon over the lip of the bottle so that no air can escape.
- Challenge a friend to blow up the balloon.
Here’s what happens”
Despite best efforts, no one will be able to blow up the balloon. As you inflate the balloon, it takes up more space in the bottle. But the bottle is already full of air! Air takes up space that we don”t always consider because we can”t see it. When you try to inflate the balloon, the air trapped inside the bottle prevents you from succeeding.
- Use two different plastic bottles and poke a hole in the end of one.
- Challenge two friends to try to blow up the balloons.
One but not the other can blow up the balloon. Which balloon can be blown up? The bottle with the hole in the end allows air to escape, making room for the balloon. The person without the hole in their bottle will still be unable to blow up their balloon.