|Quartz Crystals left, Sugar Crystals right|
Last week, we learned about crystals. First, we took a field trip to the mountains where we found quartz crystal in a stream bed. Later, we looked at sugar crystals under the microscope. The kids were pretty amazed that sugar was made up of crystals that looked so similar to quartz crystals. The last time we went to the mountain, we had bought some rock candy. This time we didn't stop in the same shop so the kids had the great idea, "Hey, mom, can we make rock candy?!" Silly question. Of course we could make rock candy! (I have quite a sweet tooth. I should be much fatter than I am.)
This is how we did it. The only downside is that you have to wait 7 days to eat it. In all honesty our crystals were pretty small. It might have been wise to wait a few days longer, but we were so excited that we just had to try them. At least they were easy enough to make again in the near future!
What makes the crystals grow?
Two different methods will contribute to the growth of the crystals on the string. You have created a supersaturated solution by first heating a saturated sugar solution (a solution in which no more sugar can dissolve at a particular temperature) and then allowing it to cool. A supersaturated solution is unstable—it contains more solute (in this case, sugar) than can stay in a liquid form—so the sugar will come out of solution, forming what's called a precipitate. This method is called precipitation.
The other is evaporation—as time passes, the water will evaporate slowly from the solution. As the water evaporates, the solution becomes more saturated and sugar molecules will continue to come out of the solution and collect on the seed crystals on the string. The rock candy crystals grow molecule by molecule. Your finished rock candy will be made up of about a quadrillion (1,000,000,000,000,000) molecules attached to the string.
from Exploratorium.com, a very awesome website
Another fun experiment is Floating M & Ms.
How To Do It:
Soak M&Ms (Skittles will work, too) in water and pay close attention to what dissolves and what floats!
What makes the letters float?
While soaking in the water, the candy shell dissolves. However, the white letters on M&Ms and Skittles are printed with edible ink that does not dissolve. So, the letters peel off and float. Too cool!
For More Cool Candy Experiments and Experiments You Can Eat, Check Out