Skip to Content

Halloween Science Experiments in a Jar

Save this idea for later!

If you love Halloween science, and you love Mason jar science experiments, stick around. You’ll love these Halloween science experiments in a jar.

Halloween is a time for spooky stories, fun costumes, and Halloween science experiments?

At our house it is! And these experiments are all Halloween science experiments in a jar.

Why? Because we love jar science experiments!

If you like these Halloween jar experiments, you’ll also like our complete list of Halloween STEM activities.

Why Halloween Science in a Jar?

We started doing science experiments in jars by accident. My kids kept breaking our “official” science flasks, so I started using glass jars instead. The glass jars were easy to use, and cost much less and were sturdier than the “real” science gear.

From there, I was asked to write the book “The Mason Jar Scientist,” and we’ve sort of stuck to jars ever since.

halloween stem challenge cards

Why Halloween Science Experiments?

halloween science experiment collage that says "halloween science in a jar"

Hands-on science experiments are not only fun for kids in elementary and middle school, but they also help children see that science and STEM subjects don’t have to be scary or intimidating.

Science is really just a structured way to explore and learn about the world. Kids can think of science as a tool for creative discovery about life and the world.

The Halloween science experiment twist just gives a fun lens to learning about science and can be used as a tool to make science less scary for kids who may not be as into science.

What Will Kids Learn Doing Halloween Science Projects?

halloween science experiment collage that says "halloween science creepy jar experiments"

In these specific jar science experiments, kids will learn about:

  • Chemical reactions
  • Chemical bonds
  • States of matter
  • Chromatography
  • Density
  • Blood
  • Crystals
  • Ionic and covalent bonds

The Complete List of Halloween Science Experiments in a Jar

halloween density jar with orange and yellow layers that says "15 halloween science experiments in jars"

These Mason jar science experiments are perfect for Halloween. Not all of these were originally done in a jar (it’s only been since 2017 that we’ve really targeted jars here at STEAMsational), but they would all work really well in jars.

A lot of these Halloween science experiments in jars are slime-related, because my kids were obsessed with slime there for a while, so we tried all sorts of slime variations!

Slime is easy to make in a jar, and we always make our slime bases in jars these days!

halloween science experiment collage that says "creepy jar experiments"

Without further ado, the Halloween science experiments in a jar!

Mix Halloween and science with this fun spooky twist on the classic marker chromatography experiment! Make ghost chromatography science!

Learn about chromatography and what colors are in a black marker with this Ghost Chromatography in a Jar experiment.

If you love Halloween AND science, you'll love this experiment to make blood boil! This boiling blood slime recipe is the perfect gross Halloween activity!

Can you make blood boil for real? You can in this Boiling Blood Slime in a Jar experiment!

Halloween science experiments and Halloween STEM activities are super fun! This Halloween density jar is a simple science experiment kids will love!

Density is more fun when it is creepy, like this Halloween Density Jar.

Make Halloween fun by making ghost slime in your science classroom! This Halloween STEM activity is the perfect Halloween science experiment for kids.

Is that a ghost? Is it slime? Is it science? It’s all three when you make Ghost Slime in a Jar.

Halloween experiments are the perfect way to introduce science to kids. Make these pickled monster eggs and delight your kids with STEM activities!

Do monsters lay eggs? How does pickling work? Does dye penetrate through an egg shell? Learn all of that and more in the Pickled Monster Eggs in a Jar experiment.

If you love science AND you love Halloween, you'll love this witch-inspired take on the classic salt crystals science project! Kids will love it!

Learn how crystals form, what type of bond salt crystals make, and what an ionic bond is in the Salt Crystals in a Mason Jar experiment.

Looking for spooky science? This eyeball slime is the perfect gross science experiment to scare kids and make science the center of Halloween activities.

We love making slime in a jar. The Eyeball Slime in a Jar experiment is particularly gross.

If you're looking for a super-simple Halloween activity to do with your kids, try this slime fun activity and make bubbling eye of toad witches brew!

Make a slime that really bubbles just like a witch’s brew in the Bubbling Eye of Toad Potion in a Jar experiment.

Halloween science projects are the perfect way to introduce science to kids. This spider leg potion is a creepy twist on a classic science experiment.

This spider leg potion isn’t made in a jar, but it could be. Make a Spider Leg Halloween Lava Lamp this Halloween!

Halloween is the perfect time to celebrate the mad scientist in all of us. Try this fun erupting potion in your Halloween science lab. It is so easy!

You don’t have to have fancy science flasks to make this Halloween Mad Scientist Lab. You can just use jars.

When October rolls around, it's time to celebrate all things creepy and gross, like zombies! This zombie slime is just gross enough to delight STEM lovers.

Make this Zombie Slime in a Jar and get creepy this Halloween.

This twist on the classic naked egg science experiment illustrates the concept of osmosis for kids in a fun and surprising way.

Red Blood Cell Osmosis for Kids Experiment

Mix science and Halloween when you make skull slime and turn it into a Halloween STEM activity! Kids of all ages will love this creepy science experiment.

Kids will love learning about chemical bonds in the Skull Slime Science Experiment.

If you have always wanted to make Halloween jello worms but never did, once you find out the science behind the experiment, you'll just HAVE to make it!

Jello Worms Experiment

Can you make slime that acts like a spiderweb? With this fun slime experiment, you can! Just two ingredients creates sticky spider silk for hours of fun!

Spiderweb Slime Recipe

halloween science experiment collage that says "15 jar science experiments for halloween"
halloween stem challenge cards

More Mason Jar Science Experiments

Your kids might also like these science experiments in a jar:

Mason Jar Science Experiments

Simple Science Experiments in Jars

Save this idea for later!