Today, you are going to learn about supersaturated solutions and crystals! We touched on these concepts last week when we learned how to make Egg Geodes. This time, you will be making your own rock candy!
Check out this link to learn more about the difference between solutions and mixtures:
- Where is sugar found?
- What is sugar made of?
- What kinds of foods do you find sugar in?
When you dissolve sugar into water, you are creating a solution. Your sugar is the solute, and your water is the solvent.
When you are creating rock candy, the supersaturated solution creates a sugar crystal precipitate. The other process that is going on is evaporation. As the water evaporates, your sugar-water solution becomes more and more saturated with sugar, thus creating sugar precipitate, aka ROCK CANDY!!!
- Adult assistance/supervision
- Glass jar
- 1/4 measuring cup
- String or wooden skewer
- Food dye (optional)
- Patience (necessary)
Here’s what to do!
1. Ask an adult for help with this project--it requires the use of a hot stove and boiling water.
2. Place the wooden skewer inside the glass jar and clip the clothespin horizontally so that the wooden skewer is suspended about 1 inch from the bottom of the jar. If you are using string, tie one end of the string around a pencil and the other end of the string around a washer or similar weighted object. This will help hold your string in place later on. Just like the skewer, suspend the string about 1 inch from the bottom of the jar.
3. Put the string or skewer aside for now.
4. Pour 1 cup of water into a pan and bring it to boil on the stove.
5. Pour 1/4 cup of sugar into the boiling water and stir it with a spoon until it dissolves completely.
6. Continue adding 1/4 cup of sugar and stirring until you can no longer get the sugar to dissolve. Make sure you continue until NO MORE will dissolve!
7. When you reach that point, remove the sugar water from the stove and let it cool for at least 20 minutes.
8. Carefully dip your string or skewer into the sugar water and then lay it aside to dry. Make sure it dries completely. Doing this will help jumpstart your sugar crystal formation, as it creates “seed crystals.” The seed crystals on the string or skewer will draw the sugar precipitate towards them as the water evaporates.
9. At this point, you can add and stir in several drops of food dye if you would like your rock candy to be colored.
10. Have an adult help you carefully pour the sugar solution into the glass jar until it is about 1 inch from the top.
11. Place your skewer or string back into the glass, and make sure it is hanging straight down the middle without touching the sides.
12. Patience! You will now need to wait for 3-7 days. Check back daily to see the progress in sugar crystal growth! Keep a log to track the growth.
Amos, E., 2012. Rock-candy-sticks. File uploaded from Wikimedia Commons on 1/15/2017.
https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Rock-Candy-Sticks.jpg/1024px-Rock-Candy-Sticks.jpg File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed.
Chris 73, 2012. SaltInWaterSolutionLiquid. File uploaded from Wikimedia Commons on 1/15/2017.
File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed.
Amos, E., 2012. Rock-Candy-Closeup. File uploaded from Wikimedia Commons on 1/15/2017.
https://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Rock-Candy-Closeup.jpg/800px-Rock-Candy-Closeup.jpg File used in accordance with the CC Attribution-Share Alike 3.0 Unported. Image was not changed.