Hot Cocoa and Marshmallows Melting Snowmen Experiment

Your kids will love this hot cocoa and marshmallows melting snowmen experiment this winter. They will also enjoy drinking the hot chocolate afterward!

Hot Cocoa Marshmallow Experiment Melted

As the weather gets cooler, it can only mean one thing … lots of hot cocoa! 

And what goes perfectly with hot cocoa? Marshmallows!

My kids are no strangers to marshmallow science experiments, and here is an easy one to teach your kids the scientific method. This hot cocoa and marshmallows melting snowmen experiment also gives your kids an opportunity to practice using a stopwatch and recording data.

The purpose of this experiment is to explore if the temperature of the hot cocoa affects how long it takes to melt a marshmallow. We also want to see if the size of the marshmallows matter when it comes to how fast they completely melt in the liquid.

This is a great experiment to do in the cold winter because who doesn’t want to just sip on hot cocoa all day long when it’s chilly out? Plus, kids always love edible science experiments since they get a yummy snack afterward.

Melting Snowmen in Hot Cocoa Experiment



1. Using a toothpick and food coloring, draw the snowmen’s faces on the marshmallows, both the regular sized ones and mini ones. You can use markers if you like, but I know the kid would want to have a taste of the marshmallows and hot cocoa after the experiment. I did make one extra regular and mini size snowmen just in case something goes wrong – always nice to have a backup!

Hot Cocoa Marshmallow Experiment Snowmen

2. Label 3 hot paper cups with the black permanent marker hot, warm, and cold. 

Hot Cocoa Marshmallow Experiment Draw Faces

3. Pour the hot cocoa mix into the three cups. I used one packet for all three cups but you can use more if you like.

4. Pour hot water into the three cups and mix.

5. Add a small ice cube to the “warm” cup and mix until the ice melts. Test it to make sure the liquid is warm. Add more ice cubes if necessary.

6. Add 2 ice cubes to the “cold” cup and mix until the ice melts. Test it to make sure the liquid is cold. Add more ice cubes if necessary.

Hot Cocoa Marshmallow Experiment Setup

7. Ask your child to form a hypothesis about which marshmallow will melt first. Make sure he specifies the temperature of the hot cocoa and the size of the marshmallow. He can record his hypothesis in the free worksheet.

8. Drop the marshmallows into the cups of cocoa all at the same time. You may want to ask your child to help you since you only have two hands! Each cup should have one big and one small marshmallow.

Observe Melting Marshmallows in Hot Cocoa

9. If you are doing this experiment with older kids, start the stopwatch as quickly as possible and record the time that it takes for the marshmallows to melt on the worksheet. If you are working with younger kids, you can just have them write “1st, 2nd, 3rd …” in the chart instead of the time.

10. Discuss the results with your kids. 

If you do not have food coloring readily available, you can skip making the snowman faces on the marshmallows. But they do make the experiment more fun! Look at how the features of the snowmen started to run as the marshmallows dissolved in the hot chocolate. Kind of look creepy!

Hot Cocoa Marshmallow Experiment in Hot Cup

Science Behind the Melting Snowmen in Hot Cocoa Experiment

If your kids have done marshmallow science experiments before, it’s probably not difficult for them to predict that the cup with the hot liquid will melt the marshmallows the fastest. But why?

Things melt when they get hot and turn from a solid into a liquid. When the marshmallows are in its solid state at room temperature, the molecules are packed tightly together. However, when you introduce heat, the molecules get excited and move around.

In boiling hot water, the molecules move so fast that the structure of the molecules start to loosen. As the structure starts to loosen and creates more space, there is more room for the molecules to move around. This continues until the solid marshmallow melts completely in the hot cocoa. 

Hot Cocoa Marshmallow Experiment Final Results

This is different than when we microwaved the marshmallows to add heat. In that case, the marshmallows undergo chemical changes that are not reversible. Instead of melting, the sugar inside the marshmallows starts to burn and turn brown or black.

You will also notice that the mini marshmallows melt faster than the regular ones. This is simply that there is less to melt, so the mini marshmallows will completely dissolve before the regular ones do. 

In the cold cup, the liquid is colder than the room temperature marshmallows. Eventually, the liquid will warm up to room temperature, but without additional heat, the marshmallows, both big and small, will stay in their solid states.

My kids had a lot of fun with this melting marshmallow in hot chocolate experiment and I hope yours did too. We did eat the marshmallows and drink the hot chocolate afterward, though my kids weren’t a huge fan of the cold one. Don’t worry, I made them an additional cup of hot cocoa with marshmallows for a job well done on the science experiment!

For more winter science experiments, check out:

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