Science experiment meets recipe: Let’s grow some sugar crystals!

Science experiment meets recipe: Let’s grow some sugar crystals!

*Adult supervision required. Let an adult handle the boiling water and hot sugar solution!

We’ve got a fun experiment for you, where you can create crystals, as if by magic. It does require some patience – you’ll need a few days to appreciate the final result. You can mix it up by using different colours and flavours once you get the hang of it; and you can easily double or triple the recipe to make more next time.

You’ll need

3 cups white granulated sugar

1 cup boiling water

One separate tall glass with water

1 tablespoon extra sugar on a plate

Clean, tall glass jar

Wooden skewer or popsicle stick

Clothes pins

Paper towel

Optional: food colouring and liquid flavouring extracts (try peppermint or cinnamon)

 

Instructions

First, let’s set up the jar and wooden skewer / popsicle stick. You’ll want the stick to be submerged into liquid, but not to touch the bottom or sides of your glass jar. So, use a clothes pin to grab the stick and balance the clothes pin on the mouth of the jar. You can use two clothes pins pinched together if the mouth of your jar is too wide. Once you have figured out a good set-up, put the jar aside. Make sure the glass jar has been properly cleaned.

Take your wooden skewer, dip it into the extra cup of water, and then dip it into your extra sugar that you set aside on a plate. Set it aside to dry.

Place the boiling water into a medium, microwave-proof bowl. Stir in the sugar as well as you can. If it won’t dissolve completely, put the bowl into the microwave for maximum of 10 seconds at a time, and stir again. Repeat until completely dissolved. This will form a thick syrup. If you prefer, you can also heat and mix the sugar and water on the stove-top, stirring continually.

Add a few drops of food colouring and flavouring (optional).

The solution will be hot, so be careful! Let it cool down for about 15 minutes before having an adult pour it into your glass jar.

Then, place the skewer into the glass jar, using the clothes pin to hold it into place. Remember, it should not be touching the sides or the bottom of the jar.

Place the jar somewhere it won’t be disturbed. Cover it with a paper towel to keep the solution clean, while allowing for evaporation.

The crystal sugar will form over the next few days. You’ll be able to see some changes within a few hours. Be patient, and if you see crystals forming on the top of the jar, remove them.

Once fully formed, break up any crystallisation on the surface of the liquid with a butter knife. Remove the sticks from the jar, and place them into a new glass or cup, using the clothes pins as before, so that they can hang to dry.

Once dry, they are ready to be enjoyed. You can stir them into hot tea. Store in an air-tight container to prevent humidity from making them sticky.

If you have crystalized sugar stuck to the jar, which is hard to remove with warm soap and water, place the jar in a pan full of water and have an adult heat it on the stove top so that the sugar can dissolve.

What’s happening?

Mixing the sugar and hot water together creates a “super saturated solution,” meaning the sugar could only be dissolved because the water is very hot. But as the water keeps cooling down, it won’t be able to “hold” that much dissolved sugar, and the sugar molecules are “pushed out” and re-form bonds with each other. The sugar molecules that are released prefer to attach to other sugar molecules, or an existing crystal formation, rather than starting new crystal formations. That means they will be attracted to the stick that you suspended into the solution, and the formation will grow larger and larger.

Picture credits: Gluesticks (larger picture),Happiness is homemade (inserted picture).