Description of "What affects the freezing rate of water"

Different substances have effects on the freezing rate of water through making the water more dense when the substances are added.

I'll prepare all the materials and equipment first which includes plastic cups, equal amounts of water, equal amounts of substances (soil, salt, sugar, etc) and some space in the freezer. After preparing five cups, four will have substances whereas one will just be filled with water.
Then I'll place the cups in the freezer and check on them in 30 minute intervals and record any changes. I'll repeat this every Saturday because I'm usually free and I might change the set temperature of the freezer each week, it could come up with some different results every week. (:
I guess I'll need an alarm to remind myself every 30 minutes or so. Heh.