Got any leftover boiled eggs from Easter? How about using them for an experiment!
Have you ever seen a ship in a bottle? You may have asked, "How did they do that?" It may seem like magic, but really this trick is more painstaking work than a magician's slip of the hand.
Most people just build the base of the ship outside the bottle with foldable masts. Then they slide it through and raise the masts inside the bottle with attached strings.
What if you could suck the whole boat in at once? That would be pretty neat. Well, you can't do it with a boat, but you can with an egg! How? By manipulating the relationship between temperature and pressure. It's like magic but better - it's science!
What's going on?
Wow! Was the egg pulled into the bottle? How did that happen? The key has to do with air pressure. Before the experiment, when the egg was sitting on top of the bottle, the air pressure inside the bottle was the same as it was outside the bottle. So nothing happens.
When you drop the burning paper into the bottle, the air quickly heats up and expands. Some of this expanding air pushes around the egg to escape. This is why you saw the egg vibrate and wiggle as the air whooshed past.
When the flame goes out (once there was no more oxygen left inside the bottle to burn), the air inside the bottle begins to cool. Cool air contracts, which takes up less space and exerts less pressure.
Because the egg acts as a seal, this sets up a difference in pressure - the pressure inside the bottle is less than the pressure outside the bottle. Air wants to move from high to low pressure. The higher air pressure outside pushes on the squishy, flexible egg until it is eventually pushed into the bottle.
Physics is cool, right?
If the bottle caved in instead and the egg wasn't sucked in, your bottle may be made of too thin a material. Try using a harder plastic or glass.
If the egg breaks into pieces on the way in, it may have been too big for the bottle's mouth. Try a smaller egg or a larger-mouthed bottle.
If nothing happened to the egg (it wasn't sucked into the bottle), the fire may have gone out as you dropped it into the bottle. Make sure the paper is fully lit and continues to burn when placed into the bottle.
How does this work? By blowing into it, you increased the pressure inside the bottle. This increase in air pressure pushes the egg back out!
Go ahead and eat your egg as a snack!
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