The difference in pressure will cause the egg to suck into the bottle

Sucking an egg into a bottle

Here’s an interesting experiment that we promise you’ll be talking about at school the next day.

  1. Find a bottle with a long, narrow neck and set it on the table.  The opening should be just small enough to keep the egg from falling inside.
  2. Boil and peel a egg.
  3. Have Mom or Dad drop 3 lit matches into the bottle (if Dad does the ‘dropping’ then make sure the fire extinguisher is handy).
  4. Quickly place the egg over the mouth of the bottle.

What happens? The lit matches heat the air inside the bottle. When air is heated it expands (and takes up more room). As the heated air expands, some of it escapes out the bottle. When the matches go out, the air inside the bottle cools and contracts (and takes up less room), thus creating a lower pressure inside the bottle than outside. The greater pressure outside the bottle forces the egg into the bottle.

Want to get the egg out of the bottle?  Turn the bottle upside down and blow into it.  The increased air pressure in the bottle will cause the egg to pop back out!

Reeko Note.  Reeko gets tons of email on this one so here’s a little extra help.  First off, check out the section on five tried and true rules on guaranteeing an experiment will work.   If that still doesn’t fix it then here are some additional tips…

  • Make sure the egg is boiled and peeled. Duh.
  • Drop the 3 matches in all at once.  Don’t light one match and drop in in, light another match and drop it in, light the next match and drop it in, light another match and drop it in…
  • You need to place the egg on the mouth of the bottle quickly.  Don’t dilly-dally around, enamored by the flames inside the bottle.  Drop the matches in and slam the egg on the mouth of the bottle.
  • If you’re still having problems, try scrambling the eggs…
  • If it still doesn’t work then put Vaseline on the egg and use a hammer…

Parent/Teacher/Advanced Notes

Expansion is an increase in the size of a body without the addition of material to the body. Most solids and liquids expand when they are heated and contract when they are cooled. Gases also expand when they are heated at a constant pressure. If a gas is heated in a container that prevents expansion, the pressure of the gas increases.

Heat causes expansion because it increases the vibrations of a material’s atoms or molecules. In a gas, heat also increases the speed at which the atoms or molecules move about. The increased movement forces the atoms or molecules farther apart and the body becomes larger.

Experiment Supplies

Supplies: Eggs, Glass bottle, Matches

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