11 Fun Valentine Science Experiments

Looking for a kid-friendly way to enjoy Valentine’s Day? Try some Valentine science activities at home!

Here’s a roundup of eleven fun Valentine experiments to do with your kids.
  1. Hearts Bobbing

    At www.candyexperiments.com, I love playing with candy. That’s why it was so fun to come up with a conversation hearts experiment that makes the candy dance!

  2. Foaming Elephant Toothpaste

    Add some pink or red food coloring to make Steve Spangler's foaming experiment a Valentine favorite! Not only do kids get to play with foamy bubbles, it’s an exothermic reaction that teaches chemistry.

  3. Foaming Marshmallow Hearts

    Here’s another way to make Valentine foam: microwave marshmallow hearts in a bottle. In just a short time, the melted marshmallow will start fountaining out of the bottle. (Caution--hot!)

  4. Valentine Slime

    Need a Valentine experiment that keeps your kids busy for a few minutes? This Little Bins For Little Hands activity shows how to make some fun Valentine slime.

  5. Catapult for Conversation Hearts

    Here’s a way to try physics in action from the Frogs Snails and Puppy Dog Tails blog. Build a catapult to launch hearts across the room!

  6. Invisible Valentine Messages

    Find instructions at Red Ted Art for writing Valentine messages with invisible ink!

  7. Make Your Own Stethoscope

    Here’s a creative way from Science-sparks to make your own stethoscope and listen for heartbeats as you teach your kids what a heart really does.

  8. Raining Hearts

    Watch hearts sink through different solutions in this experiment about viscosity in action from Inspiration Laboratories.

  9. Test Sour Candy

    Dissolve your candy and add baking soda to see which ones contain acid.

  10. Find the Sour Ingredients

    This mom at Inspiration Laboratories let her kid test each ingredient that makes up conversation hearts to find out which one causes the baking soda to react.
  11. Pierced Hearts

    Poke a pin right through a conversation heart--without breaking it!

A Fountain of Valentine Hearts

With marshmallows, bottle, and a microwave, you can create a Valentine's day fountain!

What you need:
  • marshmallow hearts, such as Peeps
  • empty plastic water bottle
  • parchment paper (optional)
What to do:
  1. Slide the marshmallows into the bottle. (You may want to roll each marshmallow up in parchment paper to slide it inside the bottle, then pull the parchment paper away.
  2. Microwave the bottle, watching closely to make sure it doesn't get too hot.
  3. Watch the marshmallow come fountaining out of the bottle!

What's happening:
As the marshmallows heat up, the gelatin softens while the air bubbles expand, making the marshmallows grow bigger. Since the marshmallows are trapped in a bottle with a narrow opening, the expanding marshmallow gets forced through the narrow bottle top, creating the fountain effect. <