Great Halloween Science Experiments for Kids

I’ve added a few new Halloween Science Experiments to our collection this year, so I thought I’d put them in one big round-up with lots of great ideas from other bloggers, too. Here at Science Sparks, we love making science spooky! We’ve got fizzy witchy potions, creepy chia seed slime, a spooky noise maker, a pumpkin optical illusion, spiders hidden in fizzy rocks and lots more creepy ideas.

If you try any of my Halloween Science Experiments, don’t forget to share a photo!

Halloween Science Experiments

Potions and Slime

Set up a witchy laboratory and try one of our spooky witchy potions. We’ve got potions that change colour, fizz, and potions that look and feel icky.

I set this activity up with food colouring, water, vinegar and baking soda and let the kids create their own concoctions.

Witches laboratory for Halloween — Witches Laboratory for Halloween

Try making some bubbly witchy drinks while investigating which makes the best bubbles. These are also great for a Halloween party.

We love the look of this glow in the dark slime from Left Brain Craft Brain. This would be a great activity alongside my glow in the dark oobleck!

Small child playing with oobleck containing glow in the dark paint.

Stretch and squish our Halloween slime. This would be great to give out in small tubs to trick or treaters as an alternative to candy.

Spider and Bug Experiments

Make creepy frozen hands and time how long they take to melt ( thanks to Happy Hooligans for the idea ) Can you speed up the melting? Try adding salt or warm water and watch what happens.

creepy frozen hands made using a glove and plastic spiders

How about some dancing worms like Playdough to Plato?

Watch a spider disappear as water is poured into a glass.

If you’re feeling creative, these spider drawing robots are great for learning about circuits and motors. You’ll need a small motor, wires and battery pack,k but these can be reused for lots of different science activities, so they are worth the investment.

Spider drawing robot - electricity for kids

Our spider paper plate marble run and magnet maze are lovely Halloween crafts that also double up as a science project!

A spider lollystick catapult is a great way to give friends and family a trick at Halloween!

Have some fizzy fun with fizzy rocks made from baking soda with hidden bugs inside. This is a great activity for kids who love baking soda eruptions.

Pumpkin Experiments

My pumpkin lava lamps make a great alternative to carving a pumpkin. The best thing is you can use them over and over again! Just add an effervescent vitamin tablet or Alka Seltzer when you want them to erupt. You can even save the empty jar for next year!

Make erupting pumpkins like these from Growing a Jewelled Rose.

Inspiration Laboratories has some great pumpkin oobleck that’s perfect for kids who like a messy activity.

Coffee Cups and Crayons has some brilliant pumpkin pie play dough, which is great for sensory fun or learning about forces.

Learn about chemical reactions by blowing up a pumpkin balloon without touching it!

Blow up a pumpkin balloon - baking soda reaction

Or, how about making a drip art pumpkin like The Imagination Tree? This would be great to use as a viscosity investigation.

Learn about push and pull forces with my pumpkin push and pull puppets.

How about a Guess What’s in the Pumpkin game? These cute pumpkins hide slimy spaghetti, sticky slime and other disgusting substances.

Thee small pumpkins filled with different icky materials. slimy spaghetti, slime and slimy rice

Make a face appear on a pumpkin with this fun optical illusion. Optical illusions are fantastic science activities as they are inexpensive and very easy to make.

optical illusion made with two small squares of cardboard and a pencil. A pumpkin is drawn on one piece of card and a pumpkin face on the other.

We’ve got some great ideas for learning as you carve a pumpkin.

Red Ted Art has some cute lanterns. These would be great for a science investigation covered in different types of paper to investigate which let through the most light.

Ghost Experiments

Try a dancing ghost like Inspiration Laboratories or jumping ghosts to learn about static electricity.

Our magnetic ghost is a super spooky way to learn about magnetism.

a large ghost made from white card with two smaller black card ghosts on top with googly eyes and a paperclip

Scary Experiments

Scare your friends with some creepy mirror writing and a super spooky noise maker. Try experimenting with different types of cups and ribbons to investigate how the noise changes.

Add some extra realism to a Halloween costume with some fake blood!

More Spooky Halloween Science Experiments

Keep the whole family entertained with a spooky science quiz.

Make a model of a brain with playdough.

Create a Halloween house and add some light! As an extension activity, you could make a whole street and add switches to turn the lights on and off.

Design and build a vegetable monster!

How about a spooky volcano? We used this great volcano from Learning Resources and spooked it up with some pretend cobwebs.

We had great fun with this chia seed slime ( thanks to Fun at Home with Kids for the idea ). The consistency is just perfect, and it’s completely non-toxic. We made this with chia seeds soaked in cornflour and a little water.

Once all the Halloween fun is over, why not try some of these easy ideas to help use up spare pumpkins?

Gross Science

My book, GROSS SCIENCE, is perfect for this spooky time of year. Make fake blood, red blood cell cupcakes, fake poo, bendy bones and lots more deliciously gruesome science for kids!