Thursday, October 14, 2010
Biology: More on water
This week we continued our discussion on why water is special and necessary for life. We compared how tap water, sea water, and air respond to changes in temperature. The obvious answer is: put things on the stove they get hot, put things on ice, they get cold. What's less obvious is that not everything heats and cools at the same rate, and not everything freezes and boils at the same temperature.
In the ice bath, the test tube with water and sea water cooled more slowly than the air. On the stove our results were somewhat less consistent. What we know from our more experienced collegues is that water is both relatively hard to cool and hard to heat,remaining a liquid over a wide range of temperatures. And as we discussed last week, liquid water is what it takes for life as we know to exist.