Praxis: Rock candy

By Medicine Hat News on March 10, 2018.

This week, I thought I would continue with my “Kitchen Chemistry” theme as I prepare some fun experiments for a very special Grade 5 class! Who knew that you could do some really exciting experiments with just ingredients in your kitchen? This week, I thought we would make those delicious fragile looking crystal lollipops you see in the store. They look so pretty, just waiting to be tasted; if you have some patience, they are actually quite easy to make at home. Let’s get started!

*Remember to ask an adult before you do this experiment.

Materials

– stove

– large pot

– measuring cups

– one package of powdered sugar-free drink mix

– sugar

– water

– wooden spoon

– wooden skewer

– empty glass jar with a lid

– nail

– plate

– patience

Procedure

1. Have an adult help you poke a hole in the middle of the lid with the nail. It should be large enough to push your wooden skewer into.

2. Measure your wooden skewer to see if it fits in the jar as some of them are pretty long.

3. The wooden skewer should not rest on the bottom of the jar once you put the lid on.

4. Cut if necessary with the help of an adult.

5. Sprinkle a bit of sugar on a plate and roll your skewer in the sugar. You may have to lightly wet the skewer to get the sugar to stick. You want a light coating of sugar all over it.

6. Measure 250 mL (one cup) of water. Pour into the pot.

7. Measure 750 mL (three cups) of sugar and pour it into the pot.

8. Stir in the powdered sugar-free drink mix.

9. Stir everything well.

10. Have an adult help you put it on the stove over medium heat. Stir the mixture constantly. You may notice that not all of the sugar has dissolved. This is what you want, do not worry.

11. Once the mixture boils, remove it from the heat.

12. Once the mixture has cooled, have an adult pour some of the mixture into the glass jar to about half full.

13. Take the lid with the skewer and place it gently in the jar.

14. Do not tighten the lid; just let it sit loosely on the mouth of the jar.

15. Patience.

16. Observe your skewer every day to see what is happening.

17. In a couple of days you will be amazed!

18. Enjoy once you have enough sugar crystals on the skewer. The longer you wait, the more delicious crystals there will be!

What is going on?

In this experiment, you made sugar crystals. You started out by creating a super saturated solution of sugar and water. No matter how hard you tried, you could not get any more sugar to dissolve into the water. As the water evaporates, the solution becomes more and more saturated with sugar molecules. These sugar molecules need somewhere to grow so this is why it was important that you had some sugar on your skewer before you put it into the solution. These seed crystals allowed the sugar molecules somewhere to grab onto and start growing. The rock candy crystals will continue to grow molecule by molecule.

Do not forget to register for the Regional Science Fair on March 24 at Medicine Hat College. Visit the Praxis website for all the details. I cannot wait to see you all there!

Patty Rooks is senior scientific consultant at PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook.

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