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Video:How to Do an Egg in a Bottle Trick

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This About.com video demonstrates air pressure, by causing an egg to be pulled into a bottle. Learn how to execute this experiment, and why it involves this outcome.See Transcript

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Transcript:How to Do an Egg in a Bottle Trick

Hi, I'm Jason Phipps for About.com, and today I'm going to demonstrate the egg in a bottle experiment.  

As with any experiment involving high temperatures, always have an adult perform the experiment and use the proper protection. 

What You'll Need

  • A peeled hard-boiled egg
  • A glass bottle or flask, with an opening slightly smaller than the diameter of the egg 
  • Very Hot Water (to perform the experiment)

Fill Bottle with Hot Water

Boil the water in a kettle and carefully pour the boiling water into the bottle. Fill the bottle about one-half full.  

Place Egg Over Bottle Opening

Quickly place the egg over the mouth of the bottle. Wait a few minutes until the egg is sucked into the bottle.  

How does the Egg get Pulled into the Bottle?

So what happened? If you just set the egg on the bottle, its diameter is too large for it to slip inside. The pressure of the air inside and outside of the bottle is the same, so the only force that would cause the egg to enter the bottle is gravity.

Gravity isn't sufficient to pull the egg inside the bottle. When you change the temperature of the air inside the bottle, you change the pressure of the air inside the bottle. If you have a constant volume of air and heat it, the pressure of the air increases. If you cool the air, the pressure decreases. If you can lower the pressure inside the bottle enough, the air pressure outside the bottle will push the egg into the container. 

Why is the egg pushed into the bottle when heat is applied? When you pour hot water into the bottle, the bottle and the air inside are heated, increasing the air pressure. The heated air pushes the egg out of the way, making it appear to jump on the mouth of the bottle. As the air cools, the egg settles down and seals the mouth of the bottle. Now there is less air in the bottle than when you started, so it exerts less pressure. When the temperature inside and outside the bottle is the same, there is enough positive pressure outside the bottle to push the egg inside. 

Thanks for watching, this has been Jason Phipps for About.com. To learn more, please visit us on the web at About.com.

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