Countdown to Halloween with 31 Days of Halloween STEM Activities for the month of October! Or if you really love Halloween, why not get a jump on our Halloween STEM challenges and start early? Halloween is the perfect holiday for all sorts of themed science experiments from ghosts and bats, to witches and jack o’ lanterns. We enjoy playing around with Halloween STEM ideas, and hope you will join in the spooky fun with us!


halloween STEM activities for kids


As soon as the fall season hits, my son is ready for Halloween. He can’t wait to go trick or treating of course, but he also loves our Halloween science activities.

I set up this 31 Days of Halloween STEM activities for us to do together easily at home. Some of these ideas we have tried before, and some will be completely new to us and really an experiment!

Enjoy STEM activities through the holidays and special days that kids love! The novelty of the holidays presents the perfect opportunity to experiment with classic science activities, technology, engineering, and mathematics that make up STEM.  Halloween STEM challenges you can do with preschoolers to even middle schoolers.

Our Halloween activities are easy to set up and budget-friendly, so you actually have time to try a few or all of them! I know life is busy and time is limited, but you can give kids a fun taste of science just the same with our themed Halloween STEM activities.

Check out your local dollar store and craft store for great Halloween-themed items to use for your Halloween activities. Each season we add a couple of new items! Simply clean off your Halloween items, store in zip-top bags, and place in a storage bin for use next year!

Before you get started why not put together a simple Halloween tinker kit to accompany your fun Halloween STEM challenges!!


Check out the links below to set up your Halloween STEM activities. Try one or try them all. Go in any order!


1. Halloween Slime

Learn about chemistry with our Halloween slime recipes. Our collection has everything you need for making the BEST Halloween slime including fluffy slime, erupting potions slime, pumpkin guts slime, and even taste-safe or borax-free slime. The possibilities are endless once we show you how to master slime making!

Halloween Slime

2. Rotting Pumpkin Jack Experiment

Carve a pumpkin and let it rot. Investigate what happens and explore decomposition for creepy Biology!

Pumpkin activities

3. Dissolving Candy Corn Experiment

Iconic Halloween candy mixed with simple STEM activities for a cool Halloween STEM challenge you can set up quickly.

4. Build Ghostly Stryofoam Structures

A Halloween twist on a classic STEM building activity. Challenge your kids to build the tallest ghost with this styrofoam ball project. We simply grabbed materials to use from the dollar store.

5.  Growing Crystal Pumpkins

Make your own crystal pumpkins with a fun twist on a classic borax crystal experiment.

Crystal Pumpkin experiment

6. Ghost Pumpkin Eruptions

This Halloween science experiment is going to get a bit messy, but it’s super cool! An erupting Jack O’Lantern is a must try at least once!

erupting Halloween science experiment

7.  Halloween Density Experiment

Explore the density of liquids with an easy to set up spooky Halloween liquid density experiment with items around the house.

8. Halloween LEGO Building Ideas

Build with LEGO and make some cool Halloween LEGO decorations like this spooky LEGO ghost.

9. Spider Oobleck

Spidery oobleck is cool science to explore and has only 2 basic kitchen ingredients with our easy recipe.

10. Bubbling Brew Experiment

Mix up your own bubbling brew in a cauldron fit for any little wizard or witch this Halloween season. Simple household ingredient create a cool Halloween theme chemical reaction that is just as much fun to play with as it is to learn from!

11. Vampire Blood Slime {taste safe}

Make slime taste safe and completely borax free! We tried something a little different with this Metamucil Halloween slime recipe.

12. Set Up Specimen Bottles

I am sure you have seen these grow animals before, try turning them into creepy animal specimen bottles? Kids love this simple science activity and get a huge kick out of the results. These might just be inexpensive novelty items, but there is a bit of science too!

Grow Animal Specimen Bottles Science Discovery Activity Dollar Store

13. Vampire Heart Experiment

Gelatin isn’t just for dessert! It’s for Halloween science too with a creepy gelatin heart experiment that will have your kids squealing with grossness and delight.

gelatin heart halloween science experiment

14. Build an Edible Haunted House

This super easy to build haunted house is perfect for many ages to enjoy, even the adults too!

Halloween Haunted House Activity Graham Cracker House

15. Halloween Tangrams

A fun way to pair a favorite holiday with a great, hands-on math lesson.  Create Halloween-themed pictures using simple shapes. It’s not quite as easy as it looks, but it definitely encourages kids to get thinking!

Halloween Tangrams Math Activity for Halloween STEM

16. Make Bubbling Ghosts

Build bubbling ghosts with this simple ghost experiment every scientist will enjoy!

17. Halloween Balloon Experiment

Take the Halloween Stem challenge.  Can you inflate a balloon without blowing air into it yourself? Find out how with our Halloween balloon experiment.  All you need are a few simple ingredients!

18. Set Up A Pumpkin Pulley System

Test your engineering skills to build your own pumpkin pulley simple machine for a fun Halloween STEM activity. Just a few simple items and you have a great pumpkin themed simple machine to play with indoors or outdoors.

Pumpkin Pulley Simple Machine for Kids Fall STEM Ideas

19. Pick A Pumpkin Book

Pick a Halloween Book and come up with your own STEM challenge. See our list of pumpkin books!

Pumpkin Science and STEM book activities for kids fall STEM ideas

20. Pumpkin Clock

Make your own clock using pumpkins to power it.  Really?  Yes, find out how you can make your own powered pumpkin clock for a fun Halloween STEM Challenge.

Pumpkin Clock for Fall STEM Using Potato Clock Kit

21. Race Car STEM Activities

Add a pumpkin to your race track. Engineer a pumpkin tunnel or create a jump track for your cars.

pumpkin car race track

22. Halloween Catapult

Design and build your own pumpkin catapult from Popsicle sticks for a fun Halloween STEM challenge.

Explore science, engineering, math and history with an easy Halloween popsicle stick STEM activity

23. Halloween Lava Lamp Experiment

Do you want to try a little spooky science this year? Our Halloween lava lamp experiment is perfect for young mad scientists!

Halloween Science Experiment Lava Lamp

24. Halloween Candy Buildings

Halloween {Candy} Structures. Take a look at some of our structure building ideas. You don’t have to use just candy.

Make sure to have some of those jelly pumpkins {like gumdrops} and plenty of toothpicks available!

ALSO CHECK OUT: Candy Corn Gears

25. Zombie Fluffy Slime

Brains and more brains with our homemade zombie theme fluffy slime recipe. Perfect for kids who love all things zombie for a cool Halloween STEM activity.

Easy Zombie Fluffy Slime Recipe

26. Rolling Pumpkins

Set up your own ramps from cardboard, wood, or even rain gutters. See how small pumpkins roll down different ramps and angles. Does a pumpkin roll?

Roll Away Pumpkin Physics Activity for Kids

27. Puking Pumpkin

Chemistry and pumpkins combine for a unique erupting science activity!

YOU MAY ALSO LIKE: Mini Pumpkin Volcano

28. Halloween Bath Bombs

Chemistry in the bath tub with fizzing eyeball Halloween bath bombs you can make easily with the kids. Explore a cool chemical reaction between an acid and base while you get clean!

29. Flying Tea Bag Ghosts

Think you have seen flying ghosts? Well maybe you can with this easy flying tea bag experiment. All you need are a few simple supplies for a fun floating tea bag science experiment with a Halloween theme.

30. Build a Pumpkin Fairy House 

White Pumpkin Fairy House

31. Science with Glow Sticks

Learn about Chemiluminescence with Glow Sticks {perfect for trick or treating night}.


Looking for easy to print activities, and inexpensive problem-based challenges? 

We have you covered…

Click here for your FREE STEM Activities for Halloween


Click on the image below or on the link for more awesome STEM activities for kids.