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What's Better Than Peeps? S'more Peeps!

Oh, Peeps. The colorful marshmallow treat that's a favorite springtime treat of children and grown-ups alike! In this Real Science! experiment, you'll take that delictilbe goodness and make it even better—because graham crackers and chocolate make almost anything better!

You should have a grown-up help you with this experiment. No, that isn't a sneaky trick to get you to share your Peep S'mores with your grown-ups. Sharing your Peep S'mores would be a nice gesture. But this is a safety issue. Those Peeps are going to get pretty hot!

A row of yellow chick Peeps and a row of pink chick Peeps.


  • Graham cracker
  • Chocolate bar
  • Peeps—any shape or color
  • Microwave-safe plate or bowl
  • Plate or paper towel for serving
  • Microwave


  1. Break a graham cracker in half, and place it on a plate or paper towel.  Place a piece of chocolate on one half of the graham cracker.
  2. Place a Peep on a microwave safe plate, and place it in the microwave.
  3. With help of an adult, microwave the peep for 15–20 seconds—the time will vary based upon individual microwaves. Keep an eye on the Peep and observe what happens in the microwave. Record your observations.
  4. Have a grown-up remove the Peep from the microwave, and place it on the graham cracker and chocolate. Top with a second graham cracker square.
  5. Enjoy! Note: marshmallows can become hot when melted in a microwave. A grown-up should test the s’more for temperature before allowing children to enjoy the treat. 

Where’s the Science? 

Peeps are a type of marshmallow, which are made from sugar, corn syrup and gelatin. The sugar and gelatin mixture is heated and whipped, which traps air in between the sugar and gelatin molecules. The more that is added, the fluffier the marshmallow will become. The air also helps the marshmallow hold its shape at room temperature. 

In the microwave, the air inside the marshmallow heats up, and begins to expand. This causes the marshmallow, or Peep, to grow several times its size! Be careful though, the sugar also heats up in the microwave, so the marshmallow will be hot.