Create cool crystals with science
What you’ll learn:
Hot solutions have more space between molecules allowing them to hold more of a chemical than cold water.
Saturated solutions crystalize as they cool
Borax crystal flowers
Let’s learn about solutions and physics as we make a lovely gift for Mother’s day (or really any day to be honest).
Borax crystal flowers can be made with real, fake, or sculpted pipe cleaner flowers – or you can do all three like us! Find our list below for the supplies you will need to make borax crystal flowers, then choose your method and get started.
Learn about crystal formation, the importance of water temperature, amount of Borax added, and time at the end of this post where we will explain the science behind the project.
Borax Crystal Flowers Recipe
No matter what type of crystal flower you choose to make you will need the same Borax crystal solution to start with.
Boil 4 cups of water and stir in 3/4cup of Borax crystals.
Mix until most of the Borax is dissolved. There should be some Borax crystals that rest on the bottom and do not go into solution – this lets you know that your solution is saturated (that is, no more Borax can be added in). If all of your Borax dissolves into the water, add more Borax.
Pour your Borax crystal solution into a cup that can hold your flower and hang the flower in the solution for a few hours.
Crystals will begin to form as the water cools!
Learning about our Borax crystal flowers
- Crystal: A natural solid that is made up of molecules connected together in a repeated pattern.
- Saturated: Holding as much as can be absorbed.
- Supersaturated: Holding more than can typically be absorbed by using heat.
- Solution: A liquid mixture.
- Solute: The minor component in a solution (in this case, Borax)
- Solvent: The major component in a solution (in this case, water)
What is a crystal?
A crystal is formed from molecules that like to pack themselves into an ordered array. Imagine you are playing with Lego bricks. If you build only out of 2×2 squares, and you connect them, in the same way, every time, you are making a Lego crystal.
In nature crystals often catch our eyes because of the geometric structure they hold. A common example of a crystal can be found on your kitchen table in the form of salt. Look around, can you find other common crystals nearby?
Sugar is also a crystal, as is bath salts (like Epsom), and some cleaning detergents like Borax. So are diamonds that you might find in a jewelry box or quartz you might find in a watch.
Why does the water need to be hot?
You might be wondering if you can make a Borax crystal solution with warm or even cold water. The answer is no. You can test this out by measuring how much Borax you can dissolve in cold water. Heat the water and see if you can dissolve a little more Borax into the solution.
Very hot water will dissolve the most Borax, and thus be the most saturated solution. Why hot water? As the water heats up the molecules are able to move around more and more. That is, the hot water has more space between each of the water molecules. That space between the hot water molecules is space that Borax molecules can dissolve into.
To make a crystal we need to dissolve so much Borax into the hot water that it literally gets squeezed out as the water cools and those extra little spaces disappear.
Does the amount of Borax matter?
This is another great science experiment. What happens if you have hot water, but only add in a quarter of the Borax? While there will be more space for the Borax to go (because of the water temperature), the Borax won’t need the extra space because there won’t be a whole lot of Borax to begin with.
Thus, when the water cools no crystals will form. The key here is to supersaturate the solution by dissolving the maximum amount of Borax in very hot water. Anything less means it won’t be squeezed out as the water cools, and crystals won’t form.
What do Borax crystals look like?
Borax crystals can be found in mines and are often clear to white. The molecular structure of Borax can be seen below.