# Egg physics

Egg physics
Group Size medium (6-20)
Setting indoors, outdoors
Setup Time medium (6-30 min)
Duration medium (11-30 min)
Subjects physics
Materials cooking oil, boiled eggs (3-4), a 225 ml glass bottle with mouth big enough for egg to half rest on, a strip of paper 4 inches, matches
Alias egg in a bottle
Presentation Style demonstration

## Brief Description

Students will demonstrate how air contracts and expands with temperature. They will attempt to fit an egg threw a small opening in the top of a bottle without damaging the egg.

## Objective

Demonstrate how air contracts and expands with temperature. Pressure changes as temperature changes.

## This Is How You Play

Before the activity:

Challenge a friend to push a shelled hard-boiled egg into a narrow-necked bottle without damaging the egg. Ask a grown-up to stand by during your performance because you have to drop a burning piece of paper into the bottle

The activity:

1. Put some cooking oil, butter of margarine around the mouth of the bottle.
2. Place the egg on the mouth of the bottle and challenge your friend to push it inside without breaking it.
3. When he gives up, it’s time to act as the magician. Fold the paper to form an accordion. Light one end with a match and drop it into the bottle.
4. Now quickly place the egg over the mouth of the bottle. It will be sucked into the bottle. (The burning paper has heated the air inside the bottle so that the air has expanded. When the paper stops burning, the air cools and contracts again. This creates a vacuum that will suck the egg into the bottle.)
5. Challenge your friend to get the egg out. When he’s given up, invert the bottle so that the egg drops down into the neck. Hold the bottle to your lips and blow a fast, hard blast of air into the bottle. The egg will zoom out, so get ready to catch it. ( The egg acts as a valve that opens while you’re blowing air into the bottle and then closes when you stop. The extra air is trapped inside, behind the egg, when the valve suddenly closes. That pressure forces the egg out.)