Egg in a Bottle

Use air pressure to squeeze a hardboiled egg through the mouth of a bottle.

With just a few household items, we can show you how a hard-boiled egg can squeeze right through the mouth of a bottle. The Egg in a Bottle Trick is a science classic, dating back at least a hundred years. It's a brilliant method of teaching just how powerful air pressure can be and the trick is also a great way of messing with your friends. We won't stop there, we'll also show you how to perform a gravity defying version of the trick… it's an “eggsclusive” upside-down twist!


  • Hardboiled eggs (peeled)
  • Large-mouthed bottle
  • Matches or lighter
  • Strips of paper
  • Small birthday candles
  • Scissors
  • Adult supervision
  • **You can get everything you need with the Egg in a Bottle kit!**


The Standard “Right-Side-Up” Version

  1. Using a pair of scissors, cut a strip of paper about 8″ x 1.”
  2. Carefully use a match or lighter to light the strip of paper at one end and drop it into the large-mouthed bottle.
  3. While the strip of paper is still burning in the bottle, set an egg on the mouth of the bottle.
  4. Watch carefully! With the egg sitting atop the bottle, the burning strip of paper extinguishes itself.
  5. Keep watching! The hardboiled egg slowly, then quickly, squeezes through the top of the bottle and drops to the bottom. Whoa!

Get the Egg Out of the Bottle!

  1. Want to do the experiment again? You'll need to get that egg out of the bottle. Be extra careful doing this!
  2. Put your mouth on the mouth of the bottle and forcefully blow air into the bottle.
  3. The egg will pop out of the bottle just like it popped into it!

The “Eggsclusive” Upside-Down Twist

  1. Carefully push two or three small birthday candles into the narrower end of a hardboiled egg. Make sure the candles can fit easily inside the large-mouthed bottle.
  2. Light the candles and sing a quick happy birthday song to the egg.
  3. Turn the large-mouthed bottle upside-down and slowly put the candles inside the mouth of the bottle.
  4. Allow the flames to heat up the air inside the bottle for just a few seconds and then place the mouth of the bottle against the egg. The candles will go out and with a “pop!” the egg will squeeze up into the bottle.

What's Shaped Like an Egg? A Water Balloon!

  1. Carefully fill the balloon with water so the balloon is about the size of a tennis ball. Tie it off. Make a few balloons just in case the first one breaks!
  2. Before going any further, make sure that the water balloon is slightly larger than the mouth of the bottle.
  3. Smear some water around the mouth of the bottle.
  4. Set a strip of paper on fire. Quickly put the burning strip into the bottle. Be careful you don't accidentally burn your fingers.
  5. Immediately cover the mouth of the bottle with the balloon. In just seconds, the balloon will start to wiggle around on the top of the bottle, the fire will go out, and some invisible force will literally “push” the balloon into the bottle. That’s amazing!
  6. Now that you've mastered the trick, it's on to the next challenge. Can you get the balloon back out of the bottle? Use what you learned about air and air pressure to come up with a way to get the balloon back out. Here's a hint… Try sneaking a straw alongside the balloon when you pull it out. If the outside air can get inside the bottle, the water balloon will come out!

How Does It Work?

In the traditional version of the Egg in the Bottle experiment, the burning piece of paper heats the molecules of air in the bottle and causes the molecules to move far away from each other. Some of the heated molecules actually escape out past the egg that is resting on the mouth of the bottle (that’s why the egg wiggles on top of the bottle). When the flame goes out, the molecules of air in the bottle cool down and move closer together. This is what scientists refer to as a partial vacuum. Normally the air outside the bottle would come rushing in to fill the bottle. However, that darn egg is in the way! The “push” or pressure of the air molecules outside the bottle is so great that it literally pushes the egg into the bottle.
In the Upside-Down Twist, the science is the same as the traditional Egg in the Bottle trick, but the whole thing is just inverted. It's a nice twist on a classic science demonstration… and it looks like the egg is defying gravity! Now that will mess with your friends.