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STEM Activity Spotlight: Halloween

Updated: Oct 2, 2023

By Francesca Vidal

Halloween isn't only a holiday for candy, costumes, and fun, but also a time to teach kids about STEM through Halloween-themed activities. This spooky season, dive into three STEM activities for kids of all ages to explore.

Pumpkin Crystals

photo/ Little Bins for Little Hands

Making crystals is more simple than it may seem. Requiring only a few materials, crystals are able to form within 24 hours. This STEM activity is great for kids of all ages, however parent supervision is recommended for younger children as borax powder can be unsafe if not handled properly. Alternatively, you can also cut your pumpkin in half and grow crystals on the inside.


  • Small white pumpkin

  • 3 cups of hot water

  • A container (preferably glass)

  • A spoon

  • A tablespoon

  • Borax Powder


  1. Mix 3 cups of water with 9 tablespoons of borax until the borax has been dissolved.

  2. Place the pumpkin inside the container.

  3. Pour the liquid borax solution into the container. Make sure that the pumpkin is fully submerged in the solution.

  4. After 24 hours, crystals should have formed on the pumpkin.

STEM Application

This activity is great at demonstrating how solids form when the reactants are undergoing a chemical change. When a chemical change (a change that involves a new substance forming) occurs, an indicator that a solid has formed is seeing cloudiness on the container. When the borax and water are mixed, cloudiness should occur. This is an indicator that the crystals are beginning to form. Each phase change will have an indicator whenever a chemical change has caused it to change phase. For example, when a liquid has formed you might notice that there is a change in volume or pH in the substance, and when a gas has formed you will see bubbles.

Density Experiment

photo/ Little Bins for Little Hands

Learn about density through this simple activity! This experiment is suited for kids from 5 to 10 years old. Parents may need to help their younger children pour in the materials but, apart from that, little to no parent supervision is needed. Since this activity is an experiment, allow children to make predictions about which substances will sink or float on top of each other.


  • Tall cup

  • Vegetable Oil

  • Water

  • Rubbing Alcohol

  • Corn Syrup

  • Food Coloring

  • Alka-Seltzer Tablets

  • Pasteur pipette


  1. Add the vegetable oil, water, rubbing alcohol, corn syrup, food coloring one-by-one using the pasteur pipette into the cup. Make observations whenever adding a new substance.

  2. Drop the Alka-Seltzer into the cup and watch as it starts to fizzle.

STEM Application

Water has a density of 1.00g/mL. Anything that has a density less than 1.00g/mL will float on top of water. Otherwise, substances with a density greater than the density of water will sink when poured into water. This experiment demonstrates the densities of each substance in comparison to each other. Corn syrup has the greatest density, so it should have sunk to the bottom followed by water, vegetable oil, rubbing alcohol, and food coloring.

Spider Oobleck

photo/ Little Bins for Little Hands

This final activity is better classified as an SEL activity rather than a STEM activity. It involves creating a Halloween-themed oobleck for kids to enjoy playing with. This activity is suited for kids of all ages and is pretty easy to do, requiring only 5 materials.


  • Cornstarch

  • Water

  • Plastic Spiders

  • Googly eyes

  • Cookie sheets

  • Measuring cup


  1. Mix a cup of cornstarch with ½ cups of water and pour onto a cookie sheet.

  2. Place the plastic spiders and googly eyes in the oobleck.

  3. Have fun playing with the oobleck! Try picking up the spiders and googly eyes with tweezers or just moving your hand in it.

SEL Application

Playing with oobleck is not only fun, but it can reduce your stress and anxiety levels. The smooth texture makes it a great way for kids to work on their sensory skills. Picking up the spiders and googly eyes with tweezers can also help kids work on their fine motor skills.

Works Cited

McClelland, Sarah. “Crystal Pumpkin Suspension Science Experiment for Kids.” Little Bins

for Little Hands, 4 Oct. 2016,


McClelland, Sarah. “Halloween Density Experiment Spooky for Spooky Fall STEM.” Little

Bins for Little Hands, 16 Oct. 2017,


McClelland, Sarah. “Spider Oobleck Recipe for Halloween.” Little Bins for Little Hands, 13

Sep. 2021,


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