Tuesday, November 13, 2007

Growing a crystal #1

Today, the professor handed out small bags with a white powder to me and my fellow students. As I mentioned before, I have to grow a crystal from a powder, for the professor's class. And today the powder arrived so I can start growing my crystal.

I went to the supermarket to get demineralised water. I can't use tap water, as this contains to much calcium and other substances that could affect the growing of the crystal.
Back home I mixed some powder with the water and stirred until the powder was completed dissolved. The liquid is clear again.
Then I added some more powder and mixed again, but this time not all of the powder is dissolved. That's normal as I calculated how much powder could be dissolved in the water at room temperature. By adding some more of the powder, the solution becomes saturated, thus it cannot dissolve more of the powder.

By heating the water a bit, the water can dissolved more of the powder. I put the beaker in the microwave for about 40 seconds and stirred again. Now all the powder, even the excess powder, is dissolved, resulting in a clear liquid.

When the water cools down to room temperature, the liquid remains clear, thus the solution contains more powder than it previously contained before heating. This means the solution is oversaturated. That is what is needed to start growing a crystal.

First I need a seed crystal, so I put a thin copper wire in the oversaturated liquid, in order to let a seed crystal grow on the wire.

Now I have to wait for the liquid to cool down further and let the seed crystal(s) grow. I'll check back in a few hours before I go to sleep, but I expect to see something when I wake up in the morning.

(I would post some pictures of the process, but I don't have a (digital) camera, so you'll have to believe what I'm describing)