weather

On earth, weather is an ever-changing factor. So we, as humans, have invented devices to measure it. Such devices include a thermometer for measuring temperature, a psychrometer or a hygrometer for measuring humidity, a anemometer for measuring wind speed, a wind vane or wind sock for measuring wind direction, a rain gauge for measuring precipitation, and a barometer for measuring air pressure. All these devices can be useful when constructing a weather station.
Temperature is a measure of the degree of hotness or coldness. It can be measured by a thermometer, which usually consists of a coloured liquid, such as alcohol, enclosed in a glass tube which has a scale etched on its outside. An increase in temperature causes the liquid to expand and a decrease in temperature causes the liquid to contract. The scale for temperature is Celsius. On this scale water freezes at zero and boils at one hundred. To measure air temperature, the thermometer must be shaded from the sun because sunlight...