If you ask an older relative if they have heard of an evaporative cooler, they may say no. But chances are they would recognize the idea behind the technology. Before air conditioning or other cooler types existed, people would sleep outside on a screened in porch to try to stay cool at night. They would often hang damp sheets over the screens in an attempt to cool the air. As the hot air passed through the sheet, it was cooled. And then the cool air would slowly circulate, relieving some of the heat for the sleepers.

The same idea exists today in the form of evaporative coolers. These machines are wonderful cooling mechanisms for people who live in hot, dry climates. They are also known by the name swamp coolers, but that can be misleading because they actually won