Spooky STEM: Halloween Science Activities for Kids
Halloween is the perfect time to mix candy and costumes with curiosity and creativity. Instead of just handing out sweets, why not turn this spooky season into a hands-on STEM (Science, Technology, Engineering, and Math) adventure? From bubbling pumpkin volcanoes to engineering candy catapults, the following activities are sure to thrill young scientists and engineers while sneaking in some learning.
Bubbling Potions and Fizzy Pumpkin Volcanoes 
Begin your STEM exploration by conducting simple chemistry experiments that demonstrate reactions. To create a bubbling “witch’s potion,” combine baking soda and vinegar in a clear container and observe the fizzing reaction caused by carbon dioxide gas. For a fun Halloween twist, turn a small pumpkin into a fizzy volcano: carefully hollow out the pumpkin, add a few tablespoons of baking soda, a bit of dish soap, and food coloring inside. When you pour vinegar into the pumpkin, watch as the mixture bubbles and overflows. Be sure to conduct this activity on a tray or outdoors to catch any spills.
Pumpkin Science & Math: Nature’s Halloween Marvel
Explore the anatomy and math of pumpkins by examining their seeds, pulp, and outer shell. Start by cutting open a medium pumpkin, then remove and separate the seeds from the pulp. Use a blender to mix the fibrous strands with water, creating pumpkin pulp that can be used to make slime. Additionally, practice measurement skills by having kids measure the pumpkin’s height, circumference, and weight, then compare results to develop understanding of size, volume, and scale. This activity combines biology and math in a hands-on way.
Engineering Challenges: Bridges, Catapults, and Candy Mazes
Encourage engineering thinking through building projects that focus on structure and physics. Challenge kids to construct a “Bone Bridge” using cotton swabs and tape, testing how much weight it can hold by placing small plastic spiders on it. Next, design a spider web with popsicle sticks to explore geometric shapes and balance. For physics fun, build simple catapults from plastic spoons and rubber bands to launch lightweight objects like mini pumpkins or candy corn, helping kids understand force, motion, and trajectory. Finally, design a candy corn maze on cardboard, requiring kids to plan and solve spatial puzzles.
Light, Shadows, and Crystal Creations
Introduce concepts of light and crystallization through interactive projects. Create shadow puppets using colored cellophane attached to sticks, then shine a flashlight on them in a darkened room to observe how light passes through and creates colorful shadows. Grow crystals using a simple solution of borax or sugar and water and watch crystals form over several days. These activities provide hands-on experience with light behavior and the science of crystals, adding a magical dimension to STEM learning.
Halloween is more than tricks and treats - it's an opportunity to inspire a lifelong love of science and engineering. These engaging STEM activities mix festive fun with hands-on learning that kids will remember long after the candy’s gone. Whether in the classroom or at home, these experiments and projects make Halloween a time for discovery and delight.
by Cyla Gardner, 4-H Youth Development Agent, 2025