Frankenstein Peeps Edible Mad Science
September 25, 2019
Girl eating cooked Frankenstein peep

Peeps Edible Mad Science Activity

Frankenstein Peeps Edible Mad Science

What's better than a little science in the kitchen!? Try out this Peeps Edible Mad Science activity for a birthday party, play date, or Halloween. For Day 12 of our 13 Days of Halloween Inspiration Jordan and I are bringing you fun Halloween activities for kids.

Get Your Scientists Ready!

Girl in white lab coat at Mad Science party

You'll want to get your little scientists ready with a lab coat and goggles. Remember safety first! Want to make lab coats of your own?  Here's how I did it.

Prep Your Specimen

Frankenstein Peep ready for experimenting

Frankenstein Peeps are sugar covered marshmallows that circulate in September and October. But different varieties can be found year round. Keep an eye out for Halloween Peeps as they are the most fun, but any marshmallow will work for this experiment. We'll keep our eyes on you!

Put one Peep on a microwave safe plate. Pretty easy right!?

Enter the Mad Science Chamber

Frankenstein peep in microwave

Place your plate inside the microwave and set it for 45 seconds on High.

Frankenstein peep in microwave

Now sit back and watch science at work! I'm not a big fan of staring at a working microwave but this is one time you DEFINITElY need to see this! You can see how excited my kids were about this in the video below!

Carefully Remove Mad Science Specimen

Frankenstein peep edible mad science activity

The magic happens in the microwave and you don't want to miss it because as soon as you take the plate out {could be hot so be careful!} Frankenstein starts to shrink. It's hard to believe he was even bigger than this! And I love that he started getting burn marks on his face. So perfect for a creepy Halloween activity!

Enjoy Peeps Edible Mad Science! 

Melted Peep as an Edible Mad Science Activity

After the marshmallow cools off a bit, you can enjoy this sugary mad science experiment. The sugar cooks and your once soft marshmallow has become tough like taffy and even crunchy on the edges. The more you cook it, the crunchier marshmallow gets. If you cook a mallow too long it'll end up black and burned! Which is not a nice smell.

What IS The Science Behind It? 

Girl eating cooked Frankenstein peep

Marshmallows are made up of sugar, water, gelatin, and lots and lots of air bubbles. The sugar makes them sweet, water makes them sticky, gelatin makes them stretchy, and the air bubbles create that perfect puff.

When you place them in the microwave the temperature changes and the water heats up. As the water heats it warms the air and each air bubble starts to expand, or gets larger. {Did you know that air expands as it gets warmer?} The expanding air accounts for the change in size, and the melting sugar creates holes and might even flow out.

When you remove the heat the air contracts, or get smaller, again and the puffy marshmallow shrinks. But it's not the same because the sugar has melted, changing the shape and structure forever. Once the sugar cools it hardens creating those crunchy edges. Isn't that cool?

More Marshmallow Fun

You can try this experiment with regular marshmallows, minis, huge ones, and other peeps to see how they react.

  • How long does it take them to get hard and crunchy?
  • How big do they puff up?
  • Which ones look most different after the experiment?
  • And most importantly, which ones are best to eat?
  • Anyone have graham crackers and chocolate?

Enjoy Your Party

Frankenstein peep edible mad science activity

You can only microwave so many Peeps. When you're all done, serve up your extra Peeps in a pistachio pudding cup like this one. Or tint a white chocolate pudding if pistachio isn't your jam.

What do you think? Do you know anyone who would love this Peeps Edible Mad Science Experiment? It doesn't just have to be kids! If you try it please let me know! I'll be coming out with more fun Mad Science activities and I'd love to share them with you.

Please follow us and tag @partieswithacause on Facebook and InstagramOr email a photo to hello{at}partieswithacause{dot}com 

For More Halloween Kid Activity Fun

For today Jordan created a super fun and creepy Ring Toss Kids Halloween Party Game that'll keep your little monsters busy. Then join us again tomorrow on Day 13! Our last day brings you our full Halloween Party Ideas.

Ring Toss Kids Halloween Party Game

If you’re just joining us on the 13 Days of Halloween Inspiration here’s what you missed:

Until tomorrow my friend!


  1. Beth

    I can’t believe there are actually Frankenstein peeps! Love the edible science experiment you do with them! Great idea!

  2. Susan-SugarPartiesLA

    This is such a fun idea for the kiddos and who doesn’t want a yummy treat after!

  3. Jackie

    My kids would certainly love this treat!

  4. Jennifer Digiacomo

    What an entertaining idea for an activity for the kids! Love your outside-the-box thinking!

  5. Lori

    Oh my gosh those peeps are the cutest!!

  6. Holly Hulke

    What a fun activity putting them in the microwave! I bet the kids loved it!


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Gingerbread houses in a row as table runner centerpiece for a Christmas Cookie Exchange Party I’m Bri of Parties With A Cause. I’m a mother to three crazy awesome kids, interior designer, & party planning junky. I love reading, globe trotting, and frozen yogurt. And I’m elevating the party experience one cause at a time! Read More

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