The Twelve Days of Science! Day 5: Egg Down the Chimney!

On the fifth day of Christmas Science, my mommy made with me…Santa going down the chimney!

There’s something magical about this time of year, with the lights, cocoa, songs, and holiday cheer. But one of the most persistent questions has always been… how does Santa fit down the chimney?

We decided to explore this question for the holidays. However, instead of using the familiar holiday mascot, we’re using hard boiled eggs! In today’s science experiment, we tested the effects of heat and ice on air pressure within a bottle! Our idea was that we could get the eggs into both bottles, simply by changing the air pressure!

Materials Needed:

Small/Medium hard boiled eggs
Large mouthed bottle (clean please!)
Lighter/matches (and an adult)


Boil your eggs! You’ll want a hard boiled egg, soft boiled may just leave egg yolks everywhere! Once the egg is cooked, peel the shell from the egg and set it aside.

Have an adult light a piece of paper on fire, or use a wooden matchstick. Quickly drop your burning material into the jar.

Place the egg on the mouth of the bottle.

Watch and see what happens!

What’s Happening?

The air around us is made of molecules that are in a gas stage. They’re already flying around fairly fast and far apart. When we add the flame into the bottle, we cause those molecules to move even faster and farther away from each other! This makes the air get bigger, and with nowhere to go, the pressure is increased.

This is called Expansion!

When this happens, it pushes the egg out of the way a little, allowing some of those molecules to escape. When the air cools down, the molecules move a little slower and come closer together.

This is called Contraction!

Now there is a little less air left in the bottle than there was before! When the high pressure pushed the egg, a little bit of the air escaped. Now that the air has condensed, there is a little less of it and a lot less pressure! Because of this, the air pressure is now lower on the inside of the bottle, and higher on the outside.

This difference causes the outside air to push REALLY HARD on the egg, pushing it through the bottle! Looking at the remains of that egg… thank goodness Santa isn’t a hard boiled egg!

*This is also supposed to happen with cooler temperatures, as it brings the molecules closer together while moving even slower. However, we weren’t able to create that change as we couldn’t get it to happen fast enough (the heat makes for a quick and dramatic change, while the ice made the adjustments much more slowly). The only thing we were able to get out of it was a soft push on the egg from the outer air.

We’ll see if we can talk our science center into replicating this experiment with some liquid nitrogen! In the meantime…

Happy Holidays!


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