Shift to The fact "Temperature and Humidity"

If you were standing in the Sahara Desert, the air would feel hot and dry. If you were lying on a tropical beach, it would feel hotter, even thought the temperature may be the same in both places. The reason for this difference is humidity - the amount of moisture or water vapor in the air. Humans can only tolerate a certain range body cool. But if the air is very humid, water does not evaporate so easily and sweat remains on the skin. This can be uncomfortable and makes you feel hotter. Humidity is measured with an instrument called a hygrometer. A simple hygrometer uses two thermometers: one has a bulb that is surrounded by wet cloth, while the other is dry. If the air is very dry, the wet bulb is cooled rapidly by evaporation. But if the air is very humid, little evaporation occurs and he reading of the two thermometers is almost the same.

Measuring temperature:
In 1714, the German scientist Gabriel Fahrenheit invented the temperature scale. The zero point was based on the lowest point to which the mercury fell during the winter in Germany. The freezing point of water was 32  F while the boiling point was 212F.
In 1742, the Swedish astronomer Anders Celsius proposed an alternative scale. He suggest making the freezing point of water 0C and the boiling point of water 100C