Keep food and drink cool with water
You can keep food and drinks cool on a camping trip or in an emergency without ice or a refrigerator, using the powerful cooling ability of water, which evaporates at 41 degrees, and therefore can cool stuff to 41 degrees, regardless of air temperature, as long as relative humidity is not 100%. Take a jug of water. Put it in a shallow pan. Cover it with a towel, and let the ends of the towel lie in the pan. Pour water over the towel and fill the pan. The water evaporates from the towel, which wicks more water from the pan, cooling the towel and the mass of water beneath it eventually to 41 degrees F, the point below which water stops evaporating. Theoretically, one could cool a box of food by setting it in a bigger box and covering it with a wet towel that lies in water in the larger box. I cool and keep grapes and melon slices fresh, moist and free of flies by covering their bowl with a wet towel set in a shallow pan of water. One might ...