Ewwww! That looks so gross. Yep, those were the exact words out of my son’s mouth when I placed the jiggling gelatin heart down in front of him. We have been going for a bit more creepier science activities this Halloween season like our zombie slime. This gelatin experiment is no exception. Get in on the Halloween fun with Halloween science experiments your kids will love!

Explore Jello For Halloween Science

There’s a lot of chemistry happening in the kitchen when it comes to Halloween science experiments and activities. Even the most common kitchen supplies like gelatin and jello are filled with simple science concepts that are easy to share with your kids.

A creepy, gross gelatin heart {or jello heart} makes for even creepier edible science if you choose! Make it for a party or make it for a fun Halloween science activity and let your kids explore the cool chemistry behind the jello or gelatin.

Whether you call it creepy science, gross science, or edible science, it sure is extremely cool science that you can really do with your kids. Don’t be afraid of trying simple science experiments. Make it playful and everyone will have a blast.

More Awesome Gelatin or Jello Activities

How Does Gelatin Work

Who would have thought gelatin or Jello was chemistry? I love being able to share simple science with my son when we are doing what he considers very cool activities. It just amazes all of us that science is really everywhere and easy opportunities like making simple Jello is a hands-on learning experience for both of us.

Exploring gelatin heart Halloween science experiments with jello science activity for cool chemistry with kids in the kitchen

Is Jello A Solid Or A Liquid?

Our gelatin heart below is called a semi-solid. Not quite a liquid and not quite a true solid.

Gelatin is made of long strings of amino acids {with a little hydrogen} that when heated loosen up and jiggle and slide along each other in a liquid state, but they also love water and like to stick to it {just not very well}.

As the water cools, when the gelatin is placed in the fridge, the bond between the atoms in the water and gelatin strengthen and the semi-solid gelatin forms. It’s only a weak bond though making it semi-solid.

That’s some grossly, cool, and creepy chemistry that I am pretty sure every mad junior scientist can get around for Halloween!

Get your free printable Halloween activity guide!

Halloween Gelatin Experiment

Note: This experiment is edible but unflavored with the gelatin packets we chose. Probably not tasty!


  • Gelatin or Jello Packs {we choose gelatin for the color but you could also use red jello}
  • Water
  • Pot {boil water with adult supervision}
  • spoon
  • Gelatin Heart Mold or Brain Mold (dollar store or Amazon)
  • Pipette, Skewer, Plastic Butter Knife {for dissecting and exploring}
  • Food Coloring Mixed in Water
Gelatin heart Halloween science experiment supplies and set up for jello science

How To Make A Gelatin Heart Or Brain

STEP 1. Follow the directions on the package of the gelatin or jello mix.

STEP 2. Add the gelatin or jello to your mold and remove when set.

Originally we made both a brain and a small heart, the brain didn’t fare well when we removed it from the mold. The heart was perfect though. I am wondering if a quick spray with a non-stick cooking spray would help the release.

Check out the cool gelatin science above and join us for our 31 Days of Halloween STEM Countdown

Gelatin heart Halloween science experiment dissection tray with pipette, blood colored water, butter knife and skewers. Edible science with Jello

STEP 3. Add red food coloring to a cup of water and use a pipette to add the “blood” to your brain or heart.

What happens when you cut into your gelatin heart? Learn more about the human heart with this fun heart model you can make.

More Spooky Halloween Experiments

Check out our complete list of spooky Halloween science experiments for kids!

Bonus 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!