science and Technology

Marshmallow Launcher STEM Challenge


Marshmallows are delicious to eat, perfect for melting in hot chocolate and brilliant for launching with a catapult as they are so light! This activity works well with either one full size or several small marshmallows.

Catapults are very inexpensive to make and can be used over and over again which makes them great for a school science project or group STEM challenge.

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These four different marshmallow launcher designs all work really well and can be tweaked or changed easily.

Either follow the instructions to make a launcher like one of ours or design your own with this Marshmallow Launcher STEM Challenge design sheet.

Marshmallow Launcher Designs

Craft Stick Catapult

The traditional popsicle stick catapult is very easy to make. You just need craft or popsicle sticks, elastic bands, tape and a milk bottle top.

Investigation ideas

Try different size and shape marshmallows to find out which travel the furthest.

Remember to only change one variable at a time. For example, if you’re changing the type of marshmallow use the same amount of force on the launching arm.

Triangular Pyramid Stick Catapult

Our first attempt using play dough to connect the skewers didn’t quite work as it wasn’t strong enough. We found elastic bands worked much better.

To make this catapult all you need to do is make the triangular pyramid shape with sticks ( we used BBQ skewers ) and elastic bands.

When you have a sturdy pyramid shape, use more elastic bands to attach a wooden spoon to another stick.

Use elastic bands again to attach the stick with the spoon to one corner of the pyramid and then thread another elastic band over the top of the pyramid and the spoon.

Pull back and let go!

Investigation Ideas

Try pulling the launching arm half way and then all the way back measuring how far the marshmallow travels each time.Can you make a giant version of a stick catapult?

Shoebox Marshmallow Catapult

Shoebox catapults are also easy to make and a bit less fiddly than the stick catapult. They are also stable so very simple for younger children to manipulate.

Investigation ideas

Experiment with bigger and smaller spoons to see which fire the marshmallows the furthest!

Paper Cup Marshmallow Launcher

This design is super simple and another good one for younger children.

To make a paper cup marshmallow launcher you’ll need

A paper cup with the bottom cut off.

A balloon with the end tied and the top removed.

Small marshmallows

Paper cup marshmallow catapult


Attach the balloon to the bottom of the paper cup like the image above. If it slips off try securing with an elastic band.

Fill the cup with marshmallows, pull back the balloon end and release.

The marshmallows should fly out of the launcher.

Investigation ideas

Experiment with small marshmallows to investigate how far apart they spread out when you use the full force of the launcher.

More Marshmallow Experiments

Learn about strong and weak shapes with marshmallow and spaghetti structures.

Team Cartwright has some delicious looking marshmallow play dough.

Did you know you can make your own marshmallows? It’s a bit messy and sticky but totally worth the effort. You can find out how in my book, Snackable Science.

You might also like my HUGE collection of kitchen science experiments.

Last Updated on June 24, 2022 by Emma VanstoneThe post Marshmallow Launcher STEM Challenge appeared first on Science Experiments for Kids.