Simple Halloween Science | Sinking Pumpkins

Welcome back for another STEM Saturday! We have been having such a great time working on some fun simple halloween science activities lately. We have this love for using marshmallows in science activities, so when we saw these awesome candy corn shaped marshmallows. In fact, we have always wanted to see if we could do the sinking marshmallows.

Simple Science Challenge Sinking Marshmallows

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Simple Halloween Science | Sinking Marshmallows

This activity is perfect for children that have already experienced testing variables and making conclusions. Some other experiments we have done for testing variables for Halloween include dissolving candy pumpkins, and Dissolving Peeps.

Setting up the Experiment


Halloween Themed Marshmallows (we used these candy corn shaped marshmallows)

Magnifying Glasses (optional)

Set Up:

For this experiment, we started with a discussion on whether we thought the marshmallows would sink or float. Since my kids love sink and float experiments, they already knew that the marshmallows would float. However their toddler sister had no idea, so this was a fun to do with her at a different time.

Sinking Marshmallow Experiment
Set up was easy, we set out a bowl of marshmallows and a vase for each child. Everyone got the same amount of water and one marshmallow.

Conducting the Experiment

Now for the fun. We conducted each test as a family down to the toddler trying it out and making discoveries. With each test, there were discussions about why it worked or didn’t work.

Sinking Halloween Marshmallow experiment
The fifth grader was able to explain the density of the water vs. the marshmallow, the third grader was able to come up with conclusions as to why tests weren’t working and new tests we should try. The toddler was able to describe what she was seeing. It was truly an experiment for the whole family.

Making Observations and Noticing

Simple Science Experiment

As I mentioned before, this experiment will look different every time you do it and depending on the background knowledge of your children. It has been awhile since we did any halloween science or density experiments, so we had a few more tests than you might have.

We started by having everyone predict a method of sinking that would be effective. (Your list might look different).

We talked about surface tension, density, and air while we made our guesses. This is the list we decided on:
* Poke Them
* Tear Them
* Stir Them
* Smash Them
* Add salt to the water
* Roll them (get all air out)

Can you get a marshmallow to sink

I won’t ruin the surprise of all the tests for you, but I wanted to show a few of my favorites. We really thought it was cool how the marshmallows would refuse to sink even on a toothpick. They would immediately slide back up the toothpick.

Halloween Science Sinking Pumpkins Density Experiment

Finally, we did the smash and roll tests. This was the most messy for sure, but it did the trick. The biggest key is to get ALL THE AIR out of the marshmallow. This is no small feat! I guess you could say it “pounded the concept” into the kids.

Do you have a favorite Fall Science Experiment? I would love to know! Connect with me on Facebook, Twitter, Google+, Pinterest, Instagram or subscribe by email. I can’t wait to hear your ideas.

Looking for more STEAM (Science, Technology, Engineering, Arts and Math) projects and inspiration?

Check out my new book STEAM Kids and get a FREE STEAM Kids Halloween bookif you buy during launch week! You can get both books (eBook PDF format) for only $9.99! But the sale and bonus book offer ends September 21, so grab your copy now and don’t miss out!

Get more information on STEAM Kids by clicking here.
Or go order your copy now! eBook PDF or Paperback 

STEAM Kids Book Cover      Halloween STEAM Kids


STEM Activities for kids

You can join us every Saturday for more STEM ideas for learning with your children of all ages.


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Halloween Science Activities! from Preschool Powol Packets

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Discover how to get siblings to get along even when all they do is annoy each other with the Sibling “Get Along” Poster Pack!

7 thoughts on “Simple Halloween Science | Sinking Pumpkins”

  1. What a fun experiment!! My daughter will have a blast with this as for science. Thanks for sharing!

    1. Lemon Lime Adventures

      Thank you so much!

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