For her birthday, my daughter received a grow-you-own-crystals kit: the Creativity For Kids Growing Crystals Undersea World by Faber-Castell. When we decided to break open the box and I read that the crystals grow over several hours, I realized that a 7-year-old and a 3-year-old were not going to have much patience to "watch" that.
So, I decided I wanted to create a time-lapse movie of the crystals growing, so the kids could enjoy at least that later on.
To do that, I took a Motorola DROID Razr, on loan from Verizon, and installed this Time-Lapse video recording app by Sheado.net [Android Market link]. I've used it before and it produces good results.
I then built a simple fixture from LEGO blocks to hold the phone at the right angle and elevation.
Not shown is a lamp I placed to illuminate the crystal kit. As this was going to happen over a 12-hour period, and light conditions in our kitchen were going to change a lot (from before noon to almost midnight), a constant light source was needed.
Not shown is assembly of the kit, which contains three pieces of cardboard treated with some chemical (I wasn't able to find out exactly what kind of crystals these are) that you then treat with a saline brine. The crystals start appearing within an hour after you do that.
If anyone knows what chemical reaction is involved here, please let me know.
So, here's the video:
Below are some close-ups of some of the prettier crystal growths.
Then, to top things off, we pulled out the microscope and looked at some of the crystals. Here are some at around 150X. Pretty cool.
As the stuff isn't toxic (unlike some of the older kits that use really nasty stuff that can etch granite and ruin just about any surface it gets on), it's not a bad way to spend an hour for kids (or grown-ups) interested in science.