Temperature
This is the degree of hotness or coldness of a place. The instrument used in measuring temperature is called THERMOMETER. Note that there are about four types of thermometer namely: the Maximum thermometer, Minimum thermometer, the wet bulb thermometer and the dry bulb thermometer.
A thermometer has the following parts: bulb, mercury, metal index, capillary, vacuum and glass tube. Temperature may be expressed either numerically or graphically. A line on a map joining places having the same mean annual temperature is called ISOTHERM.
Pressure
This is the Weight of the volume of air, which extends from the earth’s surface to the outmost layers of the atmosphere. It is the forces of gases exerted on the surface of the earth. Pressure is measured with an instrument called BAROMETER. Note that lines drawn on a map which joins together places of equal atmospheric pressure is termed ISOBAR.
Wind
Simply put as air in motion. It is the natural horizontal movement of air over the earth’s surface, which varies in speed and direction. Wind is measured with an instrument called WIND VANE. Anemometer is used to measure the speed of wind.
Rainfall
Is an aspect of precipitation. Precipitation therefore is the condensed water vapour that falls in the form of rain, mist, fog, dew, snow, sleet, frost and hail. Rainfall is measured with an instrument called RAIN-GUAGE.