Making rock candy is more than just sweet fun! This experiment is chock full of learning points that you can teach to your kids. Rock candy is crystal formation at it's finest. And it's oh-so-much fun to watch!
How To Make Rock Candy - Crystal Formation
- 1 Pyrex Measuring Cup
- 4, 16 oz Mason Jars
- Wooden or Plastic Candy Sticks
- Food Coloring
- 6 Cups Sugar
- 2 Cups Water
- Sauce Pan(s)
- Thread or Paper Clips
- Flavoring Extracts If Desired
1) Get your jars ready! I started by sterilizing my mason jars in boiling water. I then used sticks to stabilize the center candy stick. I did this by tying two sticks together with thread, as seen below. You can also try to stabilize the center stick with paper clips.
I prepared four jars, but you can prepare as many as you would like!
2) Next, make your syrup (this step is for adults only because it involves the stove!) I made three separate batches because I wanted to make three different colors. However, you can make just one batch as well. The rule is, add 1 part water and 3 parts sugar.
3) Boil your water in a sauce pan. Add sugar in one cup increments once water is boiling. Stir until dissolved and then add the next cup of sugar. Allow boiling for 5 minutes or so. Then, turn off the heat.
4) Let the syrup cool for 15 minutes and then add any flavoring extracts and colors that you are interested in and stir in with silicone spatulas. Do not stand too close to hot syrup when adding flavoring extract, since the flavor compounds could flash off due to the heat. Add in small amounts, only about 1/4-1/2 of a teaspoon. For color, add 4-8 drops to your syrup batches.
5) After syrup has been allowed to cool on the stove for about 15-20 minutes, get ready to pour it into your mason jars. First, wet your candy sticks and roll into sugar like you see below. This will give your rock candy crystals a starting point for growth!
6) Pour the sugar syrup into your jars. Drop in the candy stick and center it in the jar.
7) Line up your jars along your counter, so that your kids can view the crystal formation daily as it happens. Allow your rock candy to form across several days. Take the candy stick out of the glass once the mass of crystals is large enough for your liking. Allow to air dry, and then enjoy!
Sugar Crystal Formation After One Week
Grab A Magnifying Glass For a Closer Look!
1) Sugar is a disaccharide molecule composed of glucose and fructose.
2) When you add two cups of sugar to one cup of boiling water, you are making a saturated solution. The sugar molecules disassociate when dissolving in the boiling water. You are able to get more solute (sugar) into solution (water + sugar) by using boiling water than you would by using room temperature or cold water. This allows your solution to become "super saturated" as it cools.
The solution (water sugar mixture) cannot hold all of the solute (sugar) into solutions, so it will fall out in the form of crystals as the temperature decreases.
3) As your sugar syrup cools, the sugar molecules reassociate around the candy stick, forming sugar crystals (also known as the "rock candy" that you will see).