MATERIALS
Hard-boiled egg
Glass returnable milk bottle (ask at natural food stores)
Bowl of cold water
Hot tap water
Dish gloves
DIRECTIONS: First, try it yourself: Set a peeled, hard-boiled egg on the open mouth of a glass milk bottle and try to push it inside without breaking the egg (or the bottle!). Give up? Here's a better way. Place the egg into a bowl of cold water. Have an adult place the milk bottle under a stream of hot tap water for a minute or so, then, wearing dish gloves to protect her hands, empty the water down the sink. Immediately place the egg, tapered side down, on the mouth of the milk bottle. Watch carefully. The egg slowly gets sucked through the neck and--with a satisfying thunk--drops into the bottle.
WHY IT WORKS: The hot air inside the glass bottle is less dense (and thus at a lower pressure) than the cooler outside air. The difference creates suction, which pulls the squishy egg through the bottle's neck.
