I made some rock candy!
Here are some photos:
Here is the science behind it:
When you add sugar to cold water it will dissolve. If you keep adding sugar, eventually the water can't hold any more sugar, so the sugar won't dissolve. But, if the water is heated up, it can hold more sugar, and will become what is called a super saturated solution. As the water cools down, the solution becomes more unstable, because it is now cold, and cold water can't hold as much sugar as warm water. The extra sugar comes out of the solution, and then reforms as solid sugar crystals.
The sugar coming out of the solution find a very low energy surface to form candy on. As it takes less energy for the sugar crystals o form on top of each other, the sugar rolled in a skewer stick act as seed for new Crystal's to grow on top of. The more the sugar solution cools, the more water will evaporate from it over time. This means that note sugar crystals will come over time, and make your rock candy bigger!
This is how big mine got up to:
My hypothesis is that when I started growing them, I put them in a place that got used a lot. I think this disturbed how fast the sugar solution came out. I also think the reason the sugar Crystal's kept growing at the bottom of the glass, because the bottom of the glass would have low energy, as the glass wasn't shaken, only the skewer with sugar on it. Here is a picture of the sugar crystals on the bottom:
Next time what I would do differently would be I would put it in a place that doesn't get disturbed much, and maybe a different glass, so it has lots of space to grow.
That is the end of my sugar crystals experiment.
Hope you enjoyed!
Maya.
