B. D. Bossidy
Author of The Milky Way Metro
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The Egg in the Bottle Experiment
The Egg in the Bottle Experiment

Your Hypothesis:

     First you must form a hypothesis. This is a prediction of what is going to happen and why.  You can just guess or you can do research.  For information about air pressure, look in your school science book or on the internet.
     We are going to perform an experiment that shows how the temperature of the air effects air pressure.  We predict that a change in air temperature will suck an egg into a bottle.  Can you hypothesize how this works?

     Write down your hypothesis.

Collect the following items:

  • 1 hard boiled egg, peeled.
  • A clean, dry, glass bottle or jar with an opening small enough for the egg to sit on.  If you can find one, a glass milk bottle is perfect.
  • Canola oil.
  • A bowl of very warm water.
  • A bowl of ice water.
  • A hair dryer.

The Experiment:
 

  • Rub a little canola oil on the rim of the bottle and on the egg.
  • Hold the bottle in the warm water.  (Don't let the water get inside.) When it is warm to the touch, remove the bottle from the water.
  • Set the bottle upright on a flat surface.  Put the egg on top of the bottle immediately.
  • Now, hold the bottle in the ice water.  (Don't let water get inside the bottle.)  Make sure the egg stays on top of the bottle.
 Watch what happens.  As the bottle cools off, the egg is sucked inside.  Why?  

Science Facts:

     First, the warm water heats the bottle and the air inside.  This expands the air molecules.  When you place the egg over the opening, it cuts off the supply of air from the outside.
     Next, the cold water cools the bottle and the air inside.  The cool air contracts (gets smaller).  The air pressure outside the bottle is now pushing against the egg and causes the slippery egg to get sucked into the bottle.

Reverse the Process:

     To get the egg out of the bottle, you can reverse the process.  Turn the cool bottle upside down so the egg covers the opening from the inside.  You need to expand the air molecules by warming the air.  Use the hair dryer.  When the bottle is warm enough, you increase the air pressure inside the bottle and the air pressure pushes the egg out.

Pretty cool, huh?  I just love science.








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