Have you heard of the microwave marshmallow experiment? It’s really simple and a fun way to explore how the volume of gas expands a marshmallow as it heats up. My kids also enjoy this experiment because it mixes science (+ fun) with a sugary treat.
Microwave Marshmallow Experiment Supplies
- 4 (or more) Marshmallows
- Paper Towel or Microwave-safe plate
- Paper to jot down observations (I’ll share my 3-year old’s observations in italics below)
Microwave one marshmallow for 10 seconds and remove from the microwave. Compare it to an uncooked marshmallow and describe how it looks. How does it feel?
Microwave the second marshmallow for 30 seconds and remove it. How does it compare with an uncooked marshmallow? What happens to it as it cools?
Observation: It’s a little bit larger than the other one. It got dry as it cooled.
Touching the second marshmallow.
Cool, a little hole showed up in the middle after it cooled down a bit.
Microwave the third marshmallow for 50 seconds and remove from the microwave. Compare to and uncooked marshmallow right away and after it cools. How are they different? How does this marshmallow feel?
Observation: It’s huge and wrinkly and dry. It’s brown. That means it burned. That means it’s good to eat. Crunchy to eat.
The science behind the activity is explained clearly over here at The Exploratorium. In essence, the volume of gas in the marshmallow increases when the temperature increases, and then decreases as it cools down. The Exploratorium suggests not microwaving marshmallows for longer than 2 minutes, less you want a dark, stinky, burnt mess on your hands.
This project was inspired by a book we found at the library: Kitchen Science Experiments: How Does Your Mold Garden Grow?
Have you ever microwaved anything and been surprised by the outcome?