Materials: One large hard-boiled egg without its shell, a glass bottle with an opening slightly smaller than the egg, matches, and a small piece of paper.
Think there's no way that big egg can fit into the bottle's smaller opening. Think again! This one requires some help from mom, but the kids will love watching!
First, put the small piece of paper into the bottle, then light a match and drop into the bottle along with the paper. Immediately place the egg on top of the bottle, so that the opening is closed. Then watch the flame go out and the egg drop into the bottle!
What happened? The egg prevents outside air from getting into the bottle, while the flame causes the air inside the bottle to contract, creating a small vacuum, which pulls the egg in!
If you need a visual, check out this video from Steve Spangler Science.