Craft Time: Magic Egg Experiment

When you tire of our rubber egg experiment (or you break it) you can move on to experimenting with those hardboiled Easter eggs that may be sitting in your refrigerator long after the bunny has hopped along.

Materials

• Hardboiled eggs
• Wide-mouth glass drink bottle (the mouth needs to be a little smaller than the egg)
• Vegetable oil
• Matches/lighter
• A flame (piece of paper rolled up or any flammable material would work just fine)

Procedure

1. Use a paper towel to coat the inside edge of the bottle mouth with a little bit of vegetable oil for lubrication.

2. Peel the egg, then dip it in water and set it with the small end down in the mouth of the glass bottle. It should be slightly larger than the mouth of the bottle, so it doesn't fit inside.

3. Light your flame source. Lift the egg off the bottle, drop the source inside with the flame down, and quickly replace the egg. Watch the egg wiggle a little in the bottle mouth, and then get sucked inside!

How’s it work?

The answer is all about air pressure. When you first set the egg on the bottle, the air pressure inside the bottle matched the air pressure outside, so nothing happened. When you dropped the flame source into the bottle, it caused the air inside to heat up and expand rapidly. That expanding air pushed the egg aside and escaped from the bottle; that's why you probably saw the egg vibrating. When the fire consumed all the oxygen inside the bottle it created lower pressure inside the bottle than outside the bottle. The greater pressure outside the bottle forces the egg to get sucked into the bottle.

Want to get the egg out? You need to increase the pressure inside the bottle. Turn the bottle upside down and tilt it until the small end of the egg is sitting in the mouth. Now put your mouth close to the bottle and blow, forcing more air into the bottle and raising the pressure inside. When you take your mouth away, the egg should pop out – just be careful it doesn't hit you in the face!