Spooky season science with a quick bubbling brew experiment! Mix up fizzy, bubbly brew in a cauldron fit for any little wizard or witch this Halloween season. Simple household ingredients create a cool Halloween-themed chemical reaction that is just as much fun to play with as it is to learn from! Halloween is a fun time of year to try out simple science experiments with a spooky twist.


Halloween Science

Any holiday is a perfect opportunity for creating simple but AMAZING science experiments. However, we think Halloween tops the chart for cool ways to explore science and STEM all month long. From gelatin hearts to wizards brew, erupting pumpkins, and oozing slime, there are tons of spooky science experiments to try.

Make sure to join us for our 31 Days of Halloween Countdown.

Here’s another classic science experiment that gets a Halloween theme twist. Baking soda and vinegar chemical reactions are always a favorite of kids! Who wouldn’t love all the bubbling and fizzing fun? What happens when you mix an acid and base? You get a gas called carbon dioxide!

Watch the Video:

Bubbling Brew Experiment

This is a super easy to set-up fizzing science experiment that works for so many ages and abilities!

—>>>FREE STEM Activities For Halloween


  • a cauldron (or bowl)
  • baking soda
  • white vinegar
  • food coloring
  • dish soap
  • eyeballs


1. Add a heaping amount of baking soda to your bowl or cauldron.

Make sure to place your bowl on a tray, in the sink, or outside because this experiment can get messy.

2. Add a squirt of dish soap and food coloring to the baking soda.

Alternatively, you can also mix food coloring into the vinegar.

3. It’s time to add your spooky Halloween eyeballs or other accessories to the cauldron.

4. Now pour white vinegar onto the baking soda and watch the bubbling brew start up!

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Halloween science experiment baking soda vinegar witch's brewPin

What Makes Baking Soda Fizz?

Baking soda is made up of tiny particles called molecules. Each molecule of baking soda has three different elements: sodium, hydrogen, carbon, and oxygen.

Something exciting happens when baking soda comes into contact with an acid, like vinegar! The acid (vinegar) and the base (baking soda) react. The vinegar donates a hydrogen ion to the baking soda during this reaction.

The hydrogen ion combines with the bicarbonate ion in baking soda to form carbonic acid. This is unstable and quickly breaks into water and carbon dioxide gas.

The carbon dioxide gas is why baking soda starts to fizz and bubble. The gas tries to escape from the mixture, creating bubbles that rise to the surface. These bubbles make a fizzing sound and give the impression of a mini volcano eruption!

So, when you mix baking soda with an acid like vinegar, you get a fantastic fizzy reaction due to the production of carbon dioxide gas. It’s truly an exciting and visually appealing demonstration of a chemical reaction!

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Halloween Art Activities

Go ahead and add some of these favorite Halloween art activities to your countdown!

Printable Halloween STEM Activities Pack

150+ Pages of Halloween-Themed Materials!

This Halloween project pack is suitable for home, school, and group use for kids in grades Kindergarten through elementary but is scaleable for many ages and abilities.

What’s Included:

  • 25+ Halloween theme science and STEM activities with printable sheets, instructions, and helpful information all using easy-to-source materials perfect for limited-time needs. Includes a Halloween engineering pack with fun, problem-based challenges for kids to solve!
  • The skeleton activity pack includes building a skeleton challenge and a coding challenge! Try a skeleton bone bridge-building STEM challenge!
  • Halloween theme brick printable activities for hands-on learning with math that is perfect for early finishers or home fun and reinforces basic math concepts.
  • Bonus fun pack includes games and activities to round out your Halloween theme, such as I Spy, bingo, matching, Would You Rather cards, scavenger hunt, word search, A-Z Halloween hunt, and a coloring page.
  • The Halloween STEAM Pack includes artist-inspired projects by Warhol, Lichtenstein, and more!

Free Printable Halloween Worksheet

Add this quick and free Witch’s Brew printable to your activity! Instant download here.