July 21, 2013


 Temperature is  defined as the degree of hotness of air at a particular place. Generally the Maximum and the Minimum Temperature of a place is noted.
  • Highest temperature noted during a day is called Maximum Temperature while lowest temperature noted during a day is called Minimum Temperature. The average of daily Maximum and Minimum temperature is called the Daily Mean Temperature.
  • For finding out the maximum and the minimum temperature of air the weather instrument that is used is called Six's Thermometer. Temperature is measured in degrees of Celsius or Fahrenheit.
Air Pressure: The air pressure or atmospheric pressure is the weight of the vertical column of the air at a particular place.
  •  It is measured by  Aneroid Barometer and the units -Millibars.
  • Tempertaure is inversely proportional to Pressure.
 The coming down of moisture from the atmosphere as a result of condensation is known as precipitation. Types of Precipitation - rainfall, snowfall, hail etc.

Humidity: 'humidity' refers to dampness or wetness in the air.
  • It denotes the amount of water vapour present in the air at a given time and at a given temperature.
  •  It varies from place to place and from day to day because it is related to temperature.
  • It is measured by Wet and Dry Bulb Thermometer.
  • Humidity can be expressed in two ways -
  • (i) Absolute humidity or the weight of water vapor in a given volume of air. The absolute humidity is measured in number of grams per cubic centimeters.
  • (ii) Relative humidity or the ratio between the total capacity of the air for holding moisture under a given temperature and the actual amount of moisture collected by it. Relative Humidity shows whether the air is saturated or unsaturated i.e. it tells us about the actual state of the water at a given time. Relative humidity is measured or expressed in percentage.
Condition of Sky — Cloudinessor Sunshine: If the sky is cloudy or partly cloudy there can be the possibility of showers or even thunderstorms in certain areas. If, the sky is clear, the weather will be normal, with no fear of rain or storm.

Winds - is defined as the horizontal movement of the air along the surface of the earth. A wind is named from the direction it comes. The winds coming from the western side are called the Westerlies.
  • The instrument to determine the direction of the wind is known as Wind Vane while the instrument to know the speed of the wind is known as Anemometer
  • The speed of the wind is measured in kilometers per hour.
However the basic elements of both weather and climate are. however, the same, such as temperature, humidity, rainfall, pressure, winds, sunshine or cloudiness. The difference is of degree and duration.


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