How Did This Egg Get 'Bigger Than Before'?

By Ryan F. Mandelbaum on at

How did this egg get so big, bigger than before, even?

This five-minute craft is, perhaps among the best things on Facebook today. But, like many things on Facebook, it’s not quite right. So, it’s time we learn some elementary school science.

Chicken eggs, the container and food inside of which chicks develop, are cased in a calcium carbonate shell, where calcium carbonate is a common mineral found in rocks and other animal shells. Vinegar, on the other hand, contains acetic acid. When the two mix, the carbonate takes up the hydrogen ions from the acetic acid and becomes carbonic acid, which breaks down into carbon dioxide and water.

If you actually perform this experiment, you’ll notice two things: First, it produces bubbles from the carbon dioxide, and two, it might take longer than one day for all of the egg’s shell to undergo the reaction. I think when we did this experiment in elementary school we waited two or three days.

What’s left from this reaction is just a membrane layer with no shell. You’ll notice that the egg hasn’t changed. Puncture the membrane and you’ll be left with a puddle of raw egg. But the egg will indeed be “bigger than before,” as water from the vinegar passes through the membrane into the egg, which has a lower water concentration. It’s called osmosis.

The video then instructs you to put the egg into maple syrup and then, after a day, it will be “bigger than before.” I assume whatever syrup they used was also high in water, which is why it got even larger. Typically when you (or any other YouTube scientists) run this experiment, water then leaves the shell-less egg via osmosis and you’re left with a shrivelled-up mass.

The real marvel is the original ending of the video, which science cannot explain.

Anyway, don’t trust things you see on Facebook.

Featured image: Biswarup Ganguly (Wikimedia Commons)