It’s October, which means everyone is gearing up for Halloween — choosing costumes, stocking up on candy and planning out the best route that includes all the houses that give out full-sized candy bars. It’s also the perfect time to put together some Halloween science experiments. Here are some of our favorite spooky-themed science experiments that are good for all ages!
Is there anything better than making a mess when you’re setting up a science experiment? That’s exactly what you’ll get with the exothermic reaction generated by the witch’s brew. All you need for this spooky science experiment is some hydrogen peroxide, dish soap, and yeast from the baking aisle.
Yeast normally foams up during a process called proofing when you prepare to use it in baked goods, but it’s not terribly messy. If you mix yeast with plain old hydrogen peroxide, you get a super messy reaction that is safe for little ones to stick their hands in. This combination also creates an exothermic reaction, which means it generates heat.
The yeast removes oxygen from the hydrogen peroxide, leaving behind foam made of oxygen, water, and dish soap. Add a few drops of food coloring to turn your foam into a Halloween-themed witch’s brew!
Tea Bag Ghosts
You need to have an adult nearby for this experiment but it can be a fantastic way to teach little ones about air currents and convection. All you need is some tea bags. Remove the tea leaves from them and unfold the bags so you can stand the on one end. Use a sharpie to draw ghost faces on the tea bags before you set them on a fire-safe plate.
Light the top corner of the teabag on fire. The flame will travel down toward your fire-safe plate, and as it reaches the bottom of the bag, your teabag ghost will take flight, shooting up toward the ceiling.
As the bag burns, the air inside the cylinder heats up. Hot air naturally rises and as the teabag burns away, it leaves behind a light ‘ghost’ of ash that is light enough to follow the hot air up toward the ceiling. Make sure you aren’t setting your tea bag ghosts on fire anywhere that they could come into contact with anything that could burn your house down.
Growing Gummy Candy
Gummy bears are a tasty treat that everyone wants to find in their trick or treat bag but they can also be a nifty way to teach kids about osmosis. While they look like solid chewy candy, they are actually extremely porous. By leaving them in plain water overnight, you can watch them double in size. Water moves through the semi-permeable membrane that surrounds the candy, causing them to expand. They aren’t as tasty once you’ve soaked them in the water though.
On the other side of the coin, you can get those expanded gummy bears to shrink back down by moving them from freshwater to saltwater. The salt draws the water out of the gummy bears, but we wouldn’t recommend eating them after they’re full of salt. This is the same reason that you shouldn’t drink salt water because it draws the water out of your system, leading to dehydration.
What is Halloween without oobleck? We’re talked about slime before but we can’t make it through the Halloween season without mentioning our favorite non-newtonian fluid. You only need two ingredients to make oobleck — water and corn starch. For our spider oobleck, we’re going to add two more ingredients — food coloring and plastic spiders.
Non-newtonian fluids change viscosity depending on the amount of force applied to them. If you move slowly, it acts like a thick liquid but if you move quickly, it acts like a solid. Mix two parts corn starch with one part water to create your non-newtonian oobleck. While you’re mixing, add your food coloring to give it the perfect Halloween color scheme. Finally, toss in some plastic spiders and see how the fluid reacts to them! Do they sink or float? Can you fold them into the oobleck like you do with slime?
Pumpkin Brush Bots
Instead of carving jack-o-lanterns, why not turn your pumpkins into little robots that can walk across the table? These brush bots are a simple and fun way to introduce your little ones to engineering. You need a styrofoam pumpkin, a motor from an electric toothbrush, a toothbrush head and a power source like a 3V coin cell battery.
The vibration motor makes the toothbrush head walk across the tabletop. Attaching the pumpkin to the head of the toothbrush gives you a fun little Halloween themed robot. Don’t forget the googly eyes!
Which Halloween Science Experiment Do You Want To Try First?
We’ve played around with pumpkin-themed experiments before but with Halloween on the horizon, we want to know which one of these experiments you want to try first? Let us know in the comments below. If we missed your favorite spooky science experiment, let us know — we might feature it in the future!