What you need:
- A pop-up toaster
- A large thin plastic bag with no holes in it
- Four large pieces of cardboard (the size of placemats)
- Adult supervision
What to do:
1. Make a sort of wall around the toaster, using the cardboard sheets. You can just lean them against the toaster. Their job is to prevent the plastic bag from coming into contact with the toaster and burning up.
2. Insert the mouth of the bag over all four cardboard sheets.
3. Plug the toaster in without disturbing the cardboard wall and switch it on.
What happens:
The bag blows up slowly like a balloon! If you release it from the cardboard sheets, it may even rise up and away!
Why?
The arrangement you made operates much like a hot air balloon.
The toaster heats up the air inside it. Hot air expands i.e. its molecules move farther away from each other. They move into the bag as they expand and inflate it.
The increased distance between the molecules of heated air makes it lighter than the surrounding air whose molecules are still close together. So, hot air rises above the surrounding cooler air, taking the bag with it (once the bag is free from the cardboard wall, of course).
Picture Credit : Google
