Hard boiled egg (peeled)
• A bottle with an opening slightly smaller than an egg
• Long matches or a long lighter
• A candle or a strip of thick paper, such as newsprint or cardboard
What are you doing: Ask the children to put the candle or paper in the bottle, and then light it for them. Then the children put the egg in the opening of the bottle. When the flame goes out, the egg should slowly sink into the bottle.
Fantastic science: Children do not push the egg into the bottle. It is absorbed by air tightness; Air is made up of tiny particles also called particles. When the particles are far apart, the air expands and the air density (the amount of particles in a given space) decreases. As the particles get close to each other, the air thickens and the light intensity increases.
When the paper is lit, the air molecules in the bottle heat up and move faster, causing the air to expand and reduce its density. When the flame goes out, the air suddenly cools. The particles slow down and get closer to each other, which increases the density of the air and takes up less space. Normally air flows from the outside of the bottle to fill that void, but in this case the egg is on the way! The air pressure outside the bottle now pushes the egg into the bottle.
(If you want to see more magic, have the kids turn the bottle upside down and blow into the bottle, placing their mouths along the opening. If all goes well, the egg will fly.)