Kitchen Science

This morning I saw a headline about global warming that raised my personal temperature—because bad science irks me. The article (which I’m not blogger savy enough to link to) starts of by saying that sea levels will rise as the ice caps melt. This is a fairly common sentiment expressed in many global warming articles written for non-science people. And it’s not true.

Not that I’m disagreeing with global warming: I’m disagreeing with the melting ice caps=rising sea level equation.

Melting ice caps won’t significantly raise the sea level. The rising temperature of the water will do that quite efficiently though. (Melting ice caps do fuck over the polar bears, penguins, and many other creatures.)

Here’s a little experiment you can do in the comfort of your own kitchen.

Fill a plastic bottle with water. Fill it all the way up so there’s no air left. Screw the cap on. Stick it in the freezer. While you’re waiting for it to freeze, get out a pot and a measuring cup*. Pour 1 cup of water into the pot. Stick it on the stove. Apply heat until the water boils. Pour the water back into the measuring cup. It looks like there’s more water now, doesn’t it? No one snuck into the kitchen and added poured more water to your pot. When the bottle of water is completely frozen, take it out of the freezer. The sides of the bottle are distended and the cap may have popped off.

Water expands when it is heated and when it is frozen. Now, if you think about global warming in the context of the properties of water you’ve just observed, it makes sense that the rise in sea level is going to happen because water expands when it is heated.

(Oh, and because water’s rather specific specific heat, it takes water a lot longer to cool down than most substances. I'm sure you can figure out what that means.)

*Non-measuring types can eyeball this, or just leave the water on the stove until it boils over. Same thing.



Bonus Science Fact: If you fill a lasagna pan with two or three inches of ketchup and jump into it, it will hold you up. If you step into it, you’ll get ketchup all over your shoes. (The proper response to the latter is to make a disparaging comment or two about non-Newtonian fluids.)