Crystal Heart Valentine Science experiment

With Valentine's Day slowly sneaking up on us this crystal hearts Valentine science experiment is the PERFECT science experiment for kids! Kids young and old will be amazed to see the crystals form. Just follow the easy step by step directions to make your own crystal hearts!

Crystal heart valentine science experiment



For more science experiments for kids, be sure to check out this rainbow walking water,  these colour changing flowers, and this magic potion!

MORE easy science experiments


Crystal  science experiment

How do crystals grow?


Before we get to this crystal hearts Valentine science experiment, first let's talk about the science behind this... in other words, how do crystals grow?

Hot water is able to hold more Borax than cold water. This is because heated water molecules move further apart. The extra space allows the crystals to dissolve in the hot water. As the water cools, the water molecules move closer together again, which causes crystals to form.

How cool is that?!?!

crystal hearts



Valentine science experiment


Safety Notice - Adult supervision is required for this activity. Do not substitute any ingredients listed in our science experiments.


Supplies for your Valentine science experiment


  • 2 cups boiling water
  • 6-8 tablespoons borax
  • Dowel or craft stick
  • Pipe cleaner
  • String

Directions for your Valentine science experiment


STEP 1: Gather up your supplies


Before you get started, gather up all the supplies you need. This always makes activities LOADS easier!

STEP 2: Prepare your supplies


To get started, shape each pipe cleaner into a heart. For smaller hearts, cut the pipe cleaners in half and then shape them. 

How do crystals grow?

Once you've done that, tie a string to each pipe cleaner heart and then tie to a dowel or craft stick, as shown below.

valentine science experiment

STEP 3: Set up your Valentine science experiment


Next, pour the boiling water into a large cup or jug and add borax, 1 tablespoon at a time; stirring in between. Keep adding more until the water stops dissolving it.

Valentine science experiment crystal hearts

Place the pipe cleaner hearts into the water mixture, resting the craft stick on top of the cup or jug. Make sure not to let the pipe cleaner touch the bottom or sides of the cup, or each other. This is to avoid them sticking together.

How do crystals grow? science experiments for kids


STEP 4: Watch and observe


Place the jug or cup in a place that won't be disturbed and let your heart pipe cleaners sit in the mixture overnight. Remove the crystal hearts from the water the next day to observe and see the crystals that have formed.

TIP: The water mixture can be used again! Just pour the water and the crystals inside the glass into a pan and bring the water to a boil. The crystals will dissolve into the water and you can place new shapes in the solution.

Valentines science experiment for kids. Find our how do crystals grow and make your own crystal hearts.

We hope you enjoyed this fun Valentine science experiment for kids! Kids of all ages will be amazed at the crystal hearts that form. It's a great learning opportunity and such a cool science experiment to do. A great rainy day activity!!

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