The Twelve Days of Science! Day 12: Marshmallow Explosions!

On the 12th Day of Christmas Science, my mommy made with me…

Exploding snowmen and marshmallow peeps!

For our final project in The Twelve Days of Science, we’re taking a look at the science of marshmallows and experimenting with them! We have marshmallow snow people and candy cane peeps and as adorable as these candy critters are, they had better watch out! For we have been concocting some crazy plans of science and these little guys are not long for this world…

Before we get into our science experiments, however, we need to take a look at what these marshmallows are made of! Consisting primarily of sugar, water, and gelatinous proteins, the molecular structure of these confectioner’s delights is mostly open space. Essentially, marshmallows are made of fluffed up sugar water and held into place with gelatin. This allows them to have their puffy texture, keep a consistent shape, and have that sweet taste that many of us enjoy.

So, now that we’ve got a bit of an understanding of what makes up these adorable little marshmallow creatures, let’s have some fun with science!


Materials Needed:

3 large marshmallows
Food coloring
Paper Towels


1. Use your toothpicks and marshmallows to build your snowmen! We put two toothpicks in the center of the bottom marshmallow so that it would be strengthened as we added extra marshmallows on top.

2. Open your food coloring and pour a few drops into the food coloring cap. Dip a toothpick into the food coloring and use it to paint a face onto your snowman. We were very pleasantly surprised to find out just how easy this was and how beautiful it looked!

3. Break a toothpick in half and bend down the broken edges. These will be your snowmen arms!

4. After making a few snowmen (at least one for your experiment, and others for you to eat!), pick one out and set it on a plate.

5. Microwave your snowman on high for one minute. Every five seconds, take the snowman out of the microwaves to show your kids what is happening to it! It takes about 10 seconds for it to start puffing up to gigantic proportions!

6. After your marshmallow snowman has reached its full size, take it out and let the kids examine it. It will be very hot at first, so give it a couple of minutes to cool down. Let your kids touch it, poke at it, and closely examine the colors of the snowman. If you’ve left any others out, compare it with them! Look for similarities and differences between the two snow specimens.

What’s Happening?

You’ll notice that when you put the marshmallow snowman in the microwave, it grew into a HUGE size pretty quickly. Why did this happen? Well, as we learned earlier, marshmallows are made primarily of sugar, water, and gelatin, and have been puffed up with air. The molecules in this gas are set far apart. When you added heat to the mixture, this excited all of the molecules in the marshmallows. The water began heating up and turning into steam, which softened the gelatinous texture of the marshmallow. This softer boundary allowed for quick expansion as the rest of the molecules started bouncing around like crazy!

You may also see some discoloration on the inside of your snowman. If you see brown or black colors, this means that the sugar has heated up so much that it’s melted! It has caramelized and has turned into hard, crystalline structure.

Now that we had blown up our marshmallow snowman, it was time for us to take a look at those other little marshmallow creatures…. The Peeps.


Materials Needed:

Marshmallow peeps!
4 shallow bowls or cups
A variety of liquids (we used acetone, lemon juice, soda, and water)
Paper and pencil
Safety goggles and gloves


1. Have your child carefully examine the marshmallow peeps. Ask questions about what the peeps look like, what they feel like, how squishy they are, and any other observations you can make. You might want to take a ruler and measure them as well!

2. Using your pen and paper, make a data table for your experiment. We ran this experiment for 4 days, so we had four columns in which to record our data. Make sure you label what liquids you’re going to be using in your experiment! Have your child record their observations for the first day.

3. Put on your safety goggles!

4. Begin adding your liquids to their containers. Be very careful that the liquids are poured in such a way that they won’t damage any surfaces. We used acetone nail polish remover, so we were careful to pour this over the sink and to be very careful when moving our bowl around.

5. Store your experiment in a place that is out of reach of any animals or small children. Every day, take your bowls down and have your child record their observations about what they see happening to the peeps!

6. On the last day, take your peeps out of the bowls and put them on a plate. Take a careful look at each peep and have your child record their observations. What in the world happened to these peeps?!

What’s Happening?

Peeps are made of fluffed up sugar, water, and proteins in the form of gelatin. This strong gelatinous substance is fairly insoluble when it comes to water and other liquids! The sugar will dissolve, and the colored candy coating will dissolve as well, allowing the colors to seep back into the peeps. However, you won’t find any dissolving action in these marshmallow critters.

Seriously, the folks at Peep Research (yes this is a thing and it’s awesome!) tested the solubility of peeps in various solutions and found that only the incredibly caustic and toxic chemical Phenol could dissolve the peeps! It withstood all others, including sulfuric acid!

We didn’t have these chemicals on hand, so we used acetone, lemon juice, soda, and water. The water acted as our control, something for all of our other solutions to be tested and compared against. Our findings were as follows:

Peep solutions from left to right: Water, Soda, Acetone, Lemon Juice

The water was absorbed by the peep, causing it to swell a bit in size. The peep became soft in texture, and broke apart. However, the peep itself did not dissolve. Instead, we found bacteria growth feeding on the sugar from the peep! I have a feeling that if our house was a warmer temperature (e.g. this experiment was replicated in the summer), we would have seen quite a bit of mold growth.
The soda was also absorbed by the peep, causing it to swell and soften a bit. The caramel coloring in the soda (indeed in all of the peeps) was easily absorbed, turned the part of the peep that was submerged in the soda a dark brown. Interestingly, the carbon dioxide bubbles remained on the underside of the peep for two days!

The acetone also softened and swelled the peep a bit, as well as caused some color absorption. Similarly to the soda, there weren’t many other results to record. We thought this would be the solution that would dissolve our peeps, but it turned out in large part, to have very little effect!

The lemon juice gave an interesting reaction. It was the softest and most broken of the peeps we experimented with. It still didn’t dissolve, but it was very squishy, and very soft. We were surprised to see that it had a similar result compared with the water, only there was no bacterial growth on it. This is because the pH of the lemon juice creates such an acidic environment that it prohibits bacteria from colonizing and feeding off of the sugars on the peeps!

(Note: We’ve done previous experiments testing the pH of various substances in an attempt to inhibit bacteria growth. You can read about that here, and make your own shrunken heads or use your knowledge to preserve fruit!)

These experiments were a fantastic way to finish off our Twelve Days of Science projects. It’s so much fun to explore chemistry, physics, math, and engineering, with the fun of play! There is a whole world out there to be discovered, and it’s a ton of fun to explore it! You can find science all around you at any time, all you have to do is keep your eye out for it!

So enjoy your holiday season and your science explorations. I hope you all have a wonderful holiday season and a fantastic new year!



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