Make a bar graph to compare the humidity of each location. Answer questions about humidity. It has two thermometers. One thermometer is dry, or dry-bulb, giving the air temperature. The instrument is whirled around by a handle for 1 minute or so.
Evaporation causes the wet-bulb temperature to be cooler.
Relative humidity is found by finding the difference between the 2 thermometers and comparing this difference with the dry bulb reading on a chart. The rain gauge is thought to be the oldest weather instrument. Almost any straight walled container can be used to collect rain. The standard gauge catches rain in a funnel whose mouth is exactly 10 times larger than its tube that the rain is deposited into. Cut the balloon open and stretch across the mouth of the jar.