Countdown to Halloween with 31 Days of Halloween STEM projects 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!


Enjoy STEM For Halloween

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. 

Here you will find 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!

What Is STEM For Kids?

So you might ask, what does STEM actually stand for? STEM is science, technology, engineering, and math. The most important thing you can take away from this, is that STEM is for everyone!

Yes, kids of all ages can work on STEM projects and enjoy STEM lessons.  STEM activities are great for group work, too!

STEM is everywhere! Just look around.  The simple fact that STEM surrounds us is why it’s so important for kids to be a part of, use, and understand STEM.

Interested in STEM plus ART? Check out all our STEAM Activities!

From the buildings you see in town, the bridges that connect places, the computers we use, the software programs that go with them, and compasses for navigation, STEM is what makes it all possible.

Helpful STEM Resources To Get You Started

Here are a few resources that will help you introduce STEM more effectively to your kiddos or students and feel confident yourself when presenting materials. You’ll find helpful free printables throughout.


31 Days Of Halloween STEM Activities

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

New! Download this free 31 Days of Halloween calendar. Make sure to save it to your computer and then click the links to learn more about each activity. Print a copy and hang it up as a reminder all month long.

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, zombie slime, bat slime, erupting potions slime, pumpkin guts slime, and even taste-safe Halloween peeps slime. The possibilities are endless once we show you how to master slime making!

Halloween SlimePin

Rotting Pumpkin Jack Experiment

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

Dissolving Candy Corn Experiment

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

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.

Growing Crystal Pumpkins

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

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!

Halloween Density Experiment

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

Halloween LEGO Building Ideas

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

Spider Halloween Oobleck

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

Spidery Oobleck

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!

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.


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!

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.

Frozen Frankenstein Brains

Ice melting science is a real treat any time of the year, and it’s very easy to apply fun themes like this Frankenstein’s frozen brain!

Frozen Brain

Build an Edible Haunted House

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

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!

Make Bubbling Ghosts

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

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!


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.

Pick A Pumpkin Book

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


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.

Race Car STEM Activities

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

Halloween Candy Catapult

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

Halloween Catapult

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!

Candy Corn Gears

Candy is great for another awesome STEM activity for kids. Make your own gears with candy corn for a Halloween twist. Explore how gears work while you test out your engineering skills.


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.

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?

Rolling Pumpkins

Puking Pumpkin

Chemistry and pumpkins combine for a unique erupting science activity!

YOU MAY ALSO LIKE: Mini Pumpkin Volcano


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!


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.


Floating Ghost Drawing

These floating drawing experiments are super easy to do and they always amaze the kids!

Ghostly Floating Drawing

Build a Pumpkin Fairy House 

Halloween Bone Bridge Challenge

Build a bridge out of only bones (aka cotton swabs) that is a minimum of one foot long and sits at least one inch off the ground or table. Sounds too easy? Or does it!

Skeleton Bridge

Halloween LEGO Challenge Cards

Add these free Halloween LEGO challenge cards or task cards to your bin of bricks! Celebrate spooky fun with building LEGO!

Roll A Skeleton Halloween Game

Add some math to your Halloween STEM activities. This fun printable game involves rolling a dice to get the corresponding skeleton part. Then, kids make the parts out of playdough and add them to the coffin. The result is a whole skeleton lying in a coffin!

Also check out our printable roll a Jack O’Lantern game.


Halloween Art Activities

Go ahead and add some of these favorite Halloween art activities to your countdown!

Printable Halloween STEM Activities Pack

150+ Pages of Halloween-Themed Materials!

This Halloween project pack is suitable for home, school, and group use for kids in grades Kindergarten through elementary but is scaleable for many ages and abilities.

What’s Included:

  • 25+ Halloween theme science and STEM activities with printable sheets, instructions, and helpful information all using easy-to-source materials perfect for limited-time needs. Includes a Halloween engineering pack with fun, problem-based challenges for kids to solve!
  • The skeleton activity pack includes building a skeleton challenge and a coding challenge! Try a skeleton bone bridge-building STEM challenge!
  • Halloween theme brick printable activities for hands-on learning with math that is perfect for early finishers or home fun and reinforces basic math concepts.
  • Bonus fun pack includes games and activities to round out your Halloween theme, such as I Spy, bingo, matching, Would You Rather cards, scavenger hunt, word search, A-Z Halloween hunt, and a coloring page.
  • The Halloween STEAM Pack includes artist-inspired projects by Warhol, Lichtenstein, and more!