Looking for fun Halloween experiments for kids? These quick, low-mess projects are designed for kids and grown-ups to do together, building hands-on STEM skills. Pop on a costume, cue a Halloween playlist in the KidsBeeTV app, and pick one 10-minute activity to make your home feel like a friendly mad-scientist lab.
Plan a full family night? See our tips here: How to Prepare for Halloween with KidsBeeTV.
How to Use This Guide
Each activity includes age & supervision, time, mess level, materials, clear roles (Grown-up / Kids), Safety Note, Talk & Try, and Cleanup. Choose the version that fits your child’s age.
Experiment 1: The Oozing Jack-O’-Lantern (or Cauldron)
Age & Supervision: Ages 4–8 with adult; 9+ with adult nearby.
Time: 10 minutes.
Mess: Medium (foamy).
What You’ll Need
- Small pumpkin (carved or with a hole in the top) or a plastic cauldron/bowl;
- Baking soda;
- Vinegar;
- Tray or shallow dish;
- Food coloring (green/orange/purple);
- Dish soap (optional, for extra foam);
- Safety goggles.
Instructions
Grown-up Does
- Set pumpkin/cauldron in a tray or sink.
- Pre-mix ½ cup vinegar and a few drops of food color in a spouted cup.
Kids Do
- Add 2–3 tbsp baking soda into the pumpkin/cauldron.
- Add 1 squeeze of dish soap (optional)
Together
Slowly pour in the colored vinegar and step back. Enjoy the bubbling “lava”!
The Science Bit (kid-friendly)
Mixing an acid (vinegar) and a base (baking soda) makes carbon dioxide gas, which creates bubbles. Soap traps the gas to make extra foam.
Cleanup
Scoop foam into the trash or rinse down the sink; wipe the tray.
No pumpkin? Use a bowl or a mini cauldron prop.
Next activity idea: Decorate your “lab pumpkin” with these Halloween Pumpkin Designs.
Experiment 2: The Friendly “Ghost”
Age & Supervision: Ages 4–8 with adult.
Time: 10 minutes.
Mess: Low.
What You’ll Need
- Empty plastic bottle;
- White balloon;
- Baking soda;
- Vinegar;
- Funnel or paper cone;
- Marker;
- Optional gauze/tissue.
Instructions
Grown-up Does
- Pour ½ cup vinegar into the bottle.
- Using a funnel, put 2 tsp baking soda into the balloon.
Kids Do
- Draw a ghost face on the balloon.
- Carefully stretch the balloon over the bottle neck (don’t dump the baking soda yet!).
Together
Lift the balloon so baking soda falls into the vinegar. Watch the balloon “ghost” inflate with gas!
The Science Bit
Acid + base → CO₂ gas, which fills the balloon—the ghost “comes alive.”
Cleanup
Remove balloon, pour contents down the sink with plenty of water, rinse.
Experiment 3: Monster Slime (+ Toddler-Safe Alternative)
A) Classic Stretchy Slime (Borate-activated)
Age & Supervision: 6+ with adult.
Time: 10–15 minutes.
Mess: Medium (sticky).
What You’ll Need
- ½ cup PVA school glue (white or clear);
- ½ cup warm water;
- ½ tsp baking soda;
- 1 tbsp contact lens solution (must contain boric acid/sodium borate);
- food coloring;
- glitter (optional);
- 2 bowls;
- spoon;
- airtight container.
Instructions
Grown-up Does
- In Bowl 1, mix ½ cup glue + ½ cup warm water.
- Add color + glitter (optional).
- Stir in ½ tsp baking soda.
- Slowly add 1 tbsp contact solution, stirring as slime forms.
Kids Do
- Knead the slime until it turns stretchy and less sticky. Store airtight.
Safety Note
Avoid carpets/soft fabrics; wash hands after play. If skin is sensitive, play tools (spoons, baggies) help keep contact low.
The Science Bit
Glue has long chains called polymers. The contact solution’s borates link those chains so the mixture gets stretchy.
Cleanup
Peel pieces off surfaces while dry; wipe with warm soapy water.
B) Monster Oobleck (No-Borax, Toddler-Friendly)
Age & Supervision: 3–6 with adult.
Time: 10 minutes.
Mess: Medium (but washes out).
What You’ll Need
- 1 cup cornstarch;
- ½ cup water;
- Food coloring.
Instructions
Together
Mix cornstarch with water slowly until it feels like a liquid when you pour it but a solid when you squeeze it. Add a few drops of color.
The Science Bit
Oobleck is a non-Newtonian fluid — it flows like a liquid until you push it, then it resists like a solid.
Cleanup
Let it thicken, then scrape into trash; rinse the rest with plenty of water. (Don’t pour a full bowl of oobleck straight down the drain.)
Snack break idea: Celebrate your slimy success with Best Pumpkin Chocolate Chip Cookies.
Safety Checklist (Print-Friendly)
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Eye protection for kids and adults when things bubble or splash.
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Work on a tray, tablecloth, or in the sink.
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Keep food and science tools separate; wash hands after.
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Adult handles heat, matches, and measurements for younger kids.
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Ventilate during the “Cloud-in-a-Bottle” version.
Add Some Halloween Vibes
Before you start, open a themed playlist in the KidsBeeTV app to set the mood—then jump back here to pick an activity. For decorations that pair perfectly with the Oozing Jack-O’-Lantern, try these Halloween Pumpkin Designs.
These simple, family-led science adventures add wonder (and learning!) to your Halloween. Which will you try first—the bubbling cauldron, the friendly ghost, or the stretchy slime? Happy experimenting, and Happy Halloween from KidsBeeTV!
