Halloween Science Projects

Halloween Science Projects
Find fun and spooky Halloween science projects like glowing slime, colored fire, fake blood, and dry ice fog.

October is the perfect month for spooky Halloween science projects and experiments. Here’s a collection of projects to make gooey slime, glow in the dark items, and creepy pumpkins.

Halloween Science Projects


Ectoplasm Slime – Whether or not you believe spirits generate ectoplasm (like Slimer in the movie Ghostbusters), slime is a nice addition to a Halloween party or costume. Making slime is a practical exercise in polymer science. Experiment with ingredient proportions to modify the properties of the polymer.

Glowing Slime – Build upon a basic slime recipe by adding an ingredient that either makes the slime glow under a black light or else makes it glow in total darkness using phosphorescence.

Color Changes

Halloween Clock Reaction – In this classic chemistry demonstration, a clear solution changes to bright orange and then black.

Water Into Blood Reaction – A common pH indicator changes a clear liquid into a bloody red one.

Fake Blood

Fake Blood Chemical Reaction – This chemical reaction makes fake blood. It’s used in the bleeding knife chemistry trick, a water-into-blood reaction, and for a special type of invisible ink that reveals messages written in “blood.”

Glow in the Dark Blood – There are several ways to make realistic fake blood for Halloween decorations or to use as part of a costume. One safe recipe is to combine corn syrup with non-toxic school glue. Making it glow depends on the additional ingredient you add.

Bleeding Paper – This special paper “bleeds” because of an acid-base reaction. Creepy, but cool.

Glow in the Dark

Glowing Water – Make glow water for decorations or to make creepy glowing drinks.

Glowing Face or Body Paint – Around Halloween, you can buy glowing make-up, face paint, and body paint. However, it’s easy to make it yourself, plus you have total control over the ingredients and colors.

Glow in the Dark Nail Polish – Similarly, it’s easy to make nail polish glow in the dark. Apply glowing polish to nails or to other surfaces as a waterproof coating.

Glowing Hands – Leave glowing hand prints or just make your hands glow. All you need is a common household chemical.

Colored Fire

Colored Fire – Turn flames any color of the rainbow using household ingredients.

Black Fire – Use simple physical science to make fire absorb light, turning its flames black.

More Halloween Science Projects

15 Dry Ice Projects – Dry ice makes spooky Halloween fog, eerie punch bowls, and creepy jack o’ lanterns. Here are 15 fun projects to try.

Frankenworms – Turn gummy worms into Frankenworms using the reaction between baking soda and vinegar.

Dancing Ghosts – Make paper ghosts and bats fly through the air using static electricity.

White Face Paint – This easy recipe for white face paint is perfect for a last-minute skeleton, ghost, or zombie.

Hand of Doom Punch – Serve this Halloween punch at your holiday bash. A disposable glove is used to make the hand, which can be coated with fake blood. The punch glows under a black light and can be made into a bubbling, smoking potion by adding dry ice.

LED Glowies and Throwies – It’s easy to make anything glow using an LED and a coin battery.

Science Halloween Jack o’ Lanterns

Rainbow Fire Pumpkin
Rainbow Fire Pumpkin (Anne Helmenstine)

Rainbow Flames Jack o’ Lantern – It’s easy to make a carved pumpkin burn in all the colors of the rainbow. The technique is based on the flame test used in analytical chemistry.

Safe Self-Carving Pumpkin – The self-carving pumpkin chemistry demonstration is spectacular, but slightly risky (BOOM!). Fortunately, there’s a safe method kids can use to push carved bits from a jack o’ lantern. It’s still a chemical reaction, but there’s less pressure and no risk of a fire.

Smoke Bomb Jack o’ Lantern – Smoke and purple sparks and flames erupt from a carved pumpkin.

Glow in the Dark Pumpkin – There’s no carving required, so this Halloween pumpkin can last for months.

Flamethrower Pumpkin – Turning a carved pumpkin into a colorful flamethrower might not make you particularly popular with your HOA, but it’s an exciting way to experience the effect heating metal ions has on flame color. If you live (as I do) where fire ants are a problem, you can light the pumpkin over the mound. The boric acid that makes the green color is a natural insecticide.

Red Flames Jack o’ Lantern – Is red your color? Use chemistry to make your carved pumpkin appear extra-hellish.

Fire-Breathing Dragon Pumpkin – This carved jack o’ lantern combines a dragon face with various chemistry techniques to make the pumpkin “breathe” smoke and fire.

How to Preserve a Carved Pumpkin – Here are tips to help your carved jack o’ lantern last as long as possible.

More Halloween Science

Halloween Periodic Table – If you’re performing scientific calculations that require atomic weights or knowledge of the elements, use the Halloween periodic table. It’s seasonal and factually accurate.

Homemade Mad Scientist Costume – Dress up while performing Halloween science experiments or be a mad scientist for a party. You probably don’t need anything to make this costume that you don’t already have in your closet!

Smoke Machines and Pets (or Kids) – If you’re using a smoke machine for a spooky vibe, be sure you understand the risk they can pose to children and pets. Learn how to use smoke or fog safely.

Turn a Halloween Science Project Into an Experiment

When you follow instructions to get an effect relating to science, it’s a project. Turn a Halloween project into a Halloween science experiment by changing something (the independent variable), making a prediction about what you expect to happen (the dependent variable), and conducting an experiment.

  • For example, does the bleeding paper project give the same results using different liquids to change its color? What do you think is the explanation for the results?
  • For colored fire jack o’ lanterns, does the composition of the fuel affect the color of the flames or how long they burn? Just figuring out a way to maximize the effect of a science project can become a science experiment. Make observations, take notes, and do science!