Monday, February 05, 2007

Cold Day Experiment #2

If you put two bowls of water outside which we freeze faster at -13 degrees F? One bowl is made of metal, the other of plastic. The plastic bowl has a wider diameter than the metal bowl with more surface area exposed to the cold.

Rowan's prediction - the water in the metal bowl will freeze faster, because metal is a better conductor of heat/cold than plastic.

My prediction - they will freeze at about the same rate, because the larger surface area of the plastic bowl will equalize freezing time with the conductivity of the metal bowl.

After 15 minutes of the bowls being outside on our front porch, each bowl has about equal thickness of skim ice.

At one hour, both bowls are nearly frozen - starting at the top first and then the sides with open pools of water in the middle. However, the open pool in the metal bowl appears smaller than the one in the plastic bowl.

Our two hour mark will be here in 1/2 an hour, so we'll see what the bowls look like then. So far they seem to be freezing at a pretty similar rate.

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