‘Suck’ an egg inside a narrow-necked bottle or jar: a seemingly ‘magic’ trick, accomplished via changing the air pressure inside the bottle.
What you need:
Egg, bottle with opening slightly smaller than an egg, small piece of paper, matches or lighter
What to do:
1. Boil the egg for 8-10 minutes so that it is hard boiled.
2. Peel the egg (let it cool first!).
3. (Optional) Place the peeled egg in the mouth of the bottle to see that it won’t fall in by itself, then remove the egg.
3. Light the piece of paper on fire and drop it into the bottle.
4. Place the peeled egg in the mouth of the bottle before the fire goes out.
5. The fire should go out and the egg will be sucked into the bottle.
What happens:
When the lit piece of paper is dropped into the bottle, the air in the bottle heats up and expands. Some of this air escapes through the mouth of the bottle. When the egg is placed in the mouth of the bottle, it seals the bottle, preventing outside air from entering. The fire is extinguished once oxygen in the bottle runs out (20% of the air), and the air in the bottle cools down. As the air cools down, it contracts, lowering the air pressure in the bottle. Since the air pressure outside the bottle is higher than the inside, it pushes the egg into the bottle.
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—this homescience activity written by FLEET PhD candidate Yik-Kheng Lee (RMIT)