Crystal Rock Candy!

Candy formed right in front of your eyes! In this experiment, we will be making Rock Candy which just takes 1 hour to make and 2-3 days for the crystals to form or longer for better results! Enjoy these delicious edible crystals!
Malika Remtulla
Grade 6


I think that the Crystal Rock Candy will form easily and properly.


I found a bunch of videos for the research on YouTube. Thank-you to Cookies, Cupcakes and Cardio for this video!


You can change the colour of your crystal, the flavouring and the amount of time you keep for growing. I waited 3 weeks but not all of them had crystals formed on the stick. Instead crystals formed on the sides of the cups. The crystals looked like geodes! So instead of only eating these treats, you can decorate with them too! Stick the geodes on a cake to make a fun geode cake. 


How to make Crystal Rock Candy  

(Makes 3 Crystals, depending on how big or tall your glass is. I used 6 plastic cups, but any amount should do as long as the Crystals are still made properly!)

Step 1: Boil 1 cup of water. 

Step 2: When the water is boiled, reduce the heat just a tint and add 3 cups of sugar 1/2 cups at a time stirring between each addition. The final addition should result in syrup after being mixed in. Use a wooden spoon to mix. Set the syrup aside for 15 mins. 

Step 3: While the syrup is cooling, dip 3 cake pop/lollipop sticks in water, then sprinkle lightly with a bit of sugar. Keep on a plate. 

Step 4: After 15 minutes have passed, transfer the syrup to a pitcher. You can put 1 drop of food colouring and 1 drop of flavouring to 3 plastic cups at this point. 

Step 5: Divide the syrup evenly between the 3 cups. Stir the syrup with a metal spoon so that the food colour and flavoring is mixed evenly-not too much on one side and not too less on the other. 

Step 6: Take one coated cake pop/lollipop stick and put it in the cup. You will need clothespins for this part. The trick for this experiment is to not let the stick touch the bottom or the sides of the cup(s). If the stick does touch the bottom or the sides of the cup, the crystals won't grow properly in that area. You can prevent this by clipping two clothespins onto the cake pop/lollipop stick and balancing the edges of the stick on the rim of the cup. 

Step 7: Wait 2-3 days (or more!) for the final results. The longer you wait, the more candy you will have! 

Note: After 2-3 days has passed, crack the "shell" that has formed on top of the cup with a spoon and pour the extra syrup into another cup. All that should be left are some crystals and your Rock Candy. Gently pull the end of the cake pop/lollipop stick and see if the Rock Candy comes out. Sometimes it will, sometimes it won't. If it doesn't, spray warm water on the outside of the cup while pulling at the stick. Then crunch the sides of the Rock Candy with a knife. It should come out after all the crystals holding the Rock Candy have fallen. 

Good Luck and Enjoy!


Day 1: (24 hours later). The syrup has hardened and formed a hard shell on the top of the cup. Some syrup can still be seen, and the crstals on the end of the cake pop stick are barely visible. 


Day 2: (48 hours later). The shell that is formed on the top of the glass is fully formed and no water can be seen. The crstals on the end of the cake pop stick are not visible. 


I redid the experiment and instead of only using plastic cups I used glass cups as well. Also, I used a wooden stick for some of the cups instead of the cake pop sticks. 

The results so far have been the same with some crystals forming and some not. I really do not think my conclusion will differ at all. I may leave the crystals for a longer period of time. I could also put the crystals in the fridge and see if that does anything. Although last time nothing was really changing by keeping it in the fridge or outside. In fact it made it worse in the fridge. 

The original rock candy crystals have really formed nicely around the cups but not as much around the sticks. I think that this project is more rock candy geodes instead of actual rock candy. The geodes are really shiny and could be mistaken for real crystals. 


The sugar saturates the water, creating a thick substance. This substance is syrup. You should let the syrup set so that the syrup has time to rest before you do anything with it. When you are making rock candy crystal(s), you want the syrup to latch onto something i.e pipecleaners or in this case, cake pop sticks. Pipecleaners and cake pop sticks each have their ups and downs but if you want to use a cake pop or lollipop stick, just dip the stick in water and sprinkle lightly with some sugar. Tap off the excess. Now when you want the crystals on the stick to grow properly, make sure that the stick is not touching the sides or bottom because the crystals won't grow there if they do touch the bottom (or sides). When you let the syrup set, the syrup latches onto the sugar on the stick therefore creating ice crystals and hence your crystal rock candy is formed. 


When I checked the Rock Candy on the 3rd day, many of them were deformed and some of them just slushy liquid. I decided to keep 4 Rock Candy cups in the fridge to see if that helped with the forming, and 2 Rock Candy cups outside. 

The final result was amazing. My idea to put the Rock Candy cups in the fridge worked, but when I checked one that wasn't in the fridge, I was shocked! The one that wasn't in the fridge (I tried the red Rock Candy), was so much harder to take out and bigger then the one (blue-turquoise) that was in the fridge. More surprisingly, the Rock Candy in the fridge had spots that were not filled in with crystal.  

If you're wondering where to use these fancy treats I've got a bunch of ideas for you. Maybe you were invited to a party and asked to bring some treats, these are perfect. Even for a yummy snack (if you are allowed) this is a nice sugary snack. A small get-together with an old friend can also use this snack! Just brainstorm some ideas of your own! 


What I found, is that putting the Rock Candy in the fridge did nothing. My best advice is to just wait longer. I also found out that the Rock Candy comes in different sizes, some small, some really big as shown:  unnamed.jpg

Sources Of Error

The shapes turned out wonky-nothing like I expected. 

The syrup spilt accidentally when I was moving the tray that the cups were on. 

Some did not even form! 



Cookies Cupcakes and Cardio on YouTube! 

Thank you!


I'd like to thank my mom for helping with the videoing and research as well as taking photos. 

I would also like to thank all my family members for supporting me (my brother, my cousin, my dad and my mom).