marshmallow madness

With help from a marshmallow and syringe (without the needle!), you can create pressure that's stronger than the atmosphere, right in the palm of your hand.


This experiment teaches principles of pressure, properties of foam, and ocean science. Uh, what do marshmallows have to do with the ocean? With this demonstration, you'll be able to basically see the effect of deep-sea pressure on just one marshmallow!


• Thin marker


• Plastic syringe (without the needle) to fit mini-marshmallows


• Mini-marshmallows


• Dish detergent

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STEP ONE: Draw a face or letter on the marshmallow. (This will help you see how it changes under pressure.)


STEP TWO: Pull the plunger of the syringe all the way out, and insert a marshmallow. Replace the plunger.


STEP THREE: Suck out the air by pulling the plunger. Observe the results.


STEP FOUR: Push the plunger back in. Observe the results.




The marshmallow may look solid, but it’s actually full of air pockets—a foam. When you pump air in, you increase the pressure on the marshmallows and the air inside them is compressed. When air rushes back in, the marshmallows may get larger—and if you suck it out they may get smaller.

Photographs by Lori Epstein, Nat Geo Staff
From the book Try This! Extreme
Text Copyright © 2017 Karen Romano Young

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