Valentine’s Day Science for Kids


Can I let you in on a little secret? I don’t like Valentine’s Day. It’s not a holiday my husband and I ever really celebrate. However, I do enjoy themed activities for kids, and a Valentine’s theme is no exception. Today I’ve got two super simple Valentine’s Day science activities that you can try with your kids. Not a fan of pink or red? Change the colors to anything you like.


Secret Messages

There’s something special about writing (and receiving) secret messages. There are many options to try. One of my favorite ways is using a simple number cipher. A=1, B=2, etc. You can also use other letters, symbols, or pictures to create a substitution cipher.

We like using chemistry to make secret messages, too. Write a message with a baking soda solution. Let it dry. Then, spray lemon juice or fruit juice over your message to reveal.

Check out all of the ways we’ve created secret messages here.


Valentine Oobleck

Oobleck is a corn starch and water goo that acts like a solid or a liquid depending on how much stress is applied. When stress is applied, the corn starch and water mixture acts like a solid (your hand can’t go through; you squish it like play dough). When constant stress is not applied, the mixture acts like a liquid and drips off your hands.

It’s great for sensory play. Oobleck can be messy, so I cover the play area accordingly. Clean up is easy, though. Just let the mixture dry out, and then sweep or vacuum up the corn starch.

Make it Valentine-themed by adding pink liquid watercolors or food coloring. I like to use washable liquid watercolors because food coloring has the potential to stain.

You can add plastic hearts or other Valentine-themed items. I used hearts and pink toys.

Here is the oobleck recipe I like to use:

  1. Add about 1/2 cup of corn starch to a large bowl.
  2. Slowly add up to a 1/2 cup of water. You might not need all of the water. Mix until you get the consistency you desire. If you add too much water, just add more corn starch. 
  3. Add washable liquid watercolors.


For a different experience, you can freeze the oobleck. I like to pour the oobleck into silicone heart molds before freezing. The texture and consistency will change as the oobleck melts. It pretty much doubles the play time.