This growing borax heart-shaped crystals Valentine’s Day kids science experiment is an engaging STEM activity to do with children to learn chemistry through a fun, hands-on invitation to explore. [Video Tutorial is included.]

Are you feeling love in the air? Well, we are, and the love is actually in a cup, growing beautiful crystals in the shape of hearts. You will love this classic kids’ science STEM, especially for Valentine’s Day. Most importantly, this growing heart-shaped crystals experiment will definitely bring your little one in awe! Besides, these borax crystals grow overnight, making the process quick and easy.

Safety: Always supervise your child when dealing with chemicals, and wash your hands thoroughly afterward.

Crystals are a fantastic part of the natural world; growing them is a fun project for kids.

What is a crystal?

A crystal is a solid whose constituents (atoms or molecules) are arranged in a highly ordered microscopic structure. Table salt, sugar, diamonds, and snowflakes all form crystals. Interestingly, every substance forms a unique crystal structure.

What does growing a crystal mean?

How do crystals grow or form? 

Crystals grow because of a process of nucleation when the molecules or atoms that will soon crystallize (solute) are first dissolved in a solvent. Simply said, crystals form when liquids cool and harden into solids. As the particles contact each other and connect with each other, you will watch the crystal grow. 

How to Grow Valentine Heart Borax Crystals

 In this experiment, the borax compound is dissolved in hot water. As with most solids, borax becomes less soluble the lower the temperature of the water. Thus, as this very saturated solution of borax and boiling water cools down, the water holds less of the borax. As a result, borax drops out of the solution and attaches to a pipe cleaner, forming crystals.

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Free Kindergarten Valentine’s Day Printable Pack

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Growing Heart-Shaped Crystals Experiment

This growing borax heart experiment allows little ones to become real-life scientists! Chemists are creating reactions to try to change compounds’ makeup, and here, we are causing the formation of crystals from a solution. This process is called recrystallization, where a very saturated solution cools, thus forming crystals.

Grow your own crystal heart as Valentine’s Science Experiment

Valentine’s Day Heart-Shaped Borax Crystals Supplies

Here is a list of supplies you will need to grow your own crystal heart:

1. a red pipe cleaner (or the color of your choice) 
2. a paper clip
3. a pencil or a craft stick
4. borax powder
5. water
6. a pot for boiling and a spoon
7. a glass jar

Because crystals will form clear, the pipe cleaners will give them their color, so make sure to pick the brightest colors for a pipe cleaner.

What is Borax?

Borax is a laundry booster and all-purpose cleaner. Its chemical composition is a hydrated borate of sodium, or sodium tetraborate, simply a salt of boric acid.

Why use Borax in Borax Crystals?

We use borax to grow these crystals because borax makes large, chunky crystals rather quickly. With other substances, your little scientist would have to be much more patient!

What else, other than borax, can you use to make crystals?

A lot of substances form crystals when you create a very saturated solution that you liquefy and then solidify. For example, all types of salt, such as table salt or Epsom salt, as well as sugar, like rock candy, can be used as a substitute. However, remember the growing process will be lengthier.

Borax Safety

The borax solution is not edible, and washing hands is required after handling it. Also, keep borax away from someone who puts non-food items in their mouth, like young mouthing children.

This growing borax heart-shaped crystals experiment for Valentine’s Day makes a great science activity and even a decoration to try with kids.

Instructions: How to Make Borax Crystal Hearts

How to Make a Heart

First, create a heart shape from a red pipe cleaner by folding a pipe cleaner in half. Then, bring the ends together and twist, forming the heart. Carefully bend and mold until you have the heart shape.

Next, open a paper clip and attach it to the heart (or you can use a string or an additional pipe cleaner) and secure the other end to a pencil or other stick, like a popsicle stick. 

How to Make the Borax Crystals Solution

First, add the borax powder to the water. The ratio of water to borax is 1:3, so three tablespoons of borax for each cup of water. (I made the solution with two cups of water. Thus, I used six tablespoons of borax.)

You can also add the borax directly to the boiling water.

Then, pour the borax-water solution into a pot and bring it to a boil, stirring it well to help the borax dissolve. (Hot tap water generally will not work, so you need to bring water to a boil.)

Make sure that the borax is dissolved completely and looks clear. If the water is murky or cloudy, the crystal will come out cloudy and not clear as well. Remove from heat.

Thereafter, transfer the hot water mixture to a jar or a cup about three-quarters of the way to the top. (I am using a 2-cup measuring cup.)

Lastly, position a pencil over the top of the cup so that the heart drops down into the solution, being submerged completely.

Make sure that the pipe cleaner is not touching the bottom or sides of the cup or a jar, so that they can grow as large as possible.

Video Tutorial

Watch the Valentine Heart Borax Crystals Grow

Allow the heart to sit, completely submerged in the substance, for 12-24 hours. You will notice the crystals forming after a few hours, and they will be completely formed after 24 hours. 

Remove the pencil/heart from the jar and remove the paper clip you used for hanging.

Place a crystalized heart on a paper towel or suspend it hanging to dry.

Your crystal hearts are ready to be displayed! You can also offer a child a magnifying glass to explore this cool science exploration up close. And if you have a microscope, snip a piece of a crystal and see it even closer.

Have you tried making tactile number boards? Leave a comment if you did!

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For Valentine’s Activities

See here Hearts Tactile Numbers Puzzle-Boards

For Valentine’s Crafts

See here DIY Valentine’s I-Love-You From The Button of my Heart Card.

I hope you enjoyed a DIY Growing Heart-Shaped Crystals Experiment! Leave a comment if you have tried it!

♡ Enriching the Mind one Heart at a time ♡