WEATHER

1. Elements of weather and climate

3. •Our daily economic activities of
man, like communication,
electronic services, food and
clothing etc. depend on the
elements of weather and
atmospheric conditions.

4. A. Temperature
•Temperature is the measure of how hot or
cold a thing or a place is.
•Temperature vary from place to place.
•There are various factors that affect
temperature.

5. They are:
•1. Latitude.
•2. Altitude.
•3. Nearness to the sea.
•4. Seasons.
•5. Time of the day.
•6. Vegetation.

6. Temperature is measured with the help of
Thermometer

7. B. Atmospheric pressure
•It is the pressure
exerted by the
weight of the
atmosphere on the
earth’s surface.

8. • The instrument used to
measure the atmospheric
pressure is the barometer.
• The atmospheric pressure
is measured in millibars.
• The normal atmospheric
pressure is 1013 millibars.

9. C. Prevailing winds
• The winds coming from
warmer areas like deserts
would increase the
temperature while the
winds coming from a
cooler region such as
polar region, decrease
the temperature.

10. D. Rainfall
•Rainfall is measured
by an instrument
called a Rain gauge.

11. E. Humidity
•Humidity is the amount of water vapour in the
atmosphere.
•The actual amount of water vapour present in
the atmosphere is called “absolute humidity “. It
is measured in grams per cubic meter.
•Relative humidity is the ratio between the actual
amount of water vapour present in the air and
the total amount the air can hold at a given
temperature. It is expressed in percentage.

12. •Humidity is
measured with the
of wet and dry bulb
thermometer. It is
also called as
Hygrometer.

13. F. Sunshine
•Sunshine is determined by the
season and latitude of a place.
•Cloudy skies keep out sunshine and
affects weather.

14. G. Cloud
• A cloud is a mass of small water droplets or tiny ice
Crystal’s that float in the air.

15. Based on their shape and height where they
are formed the clouds are classified as:
•Cirrus clouds:
•These are feathery
clouds which form at
very high levels of 5 to
10 km.

16. Cumulus clouds
•These are cauliflower
shaped clouds and
they cause rainfall with
lightning and thunder
and are usually white
or grey in colour.

17. Stratus clouds
•These are sheet-like
clouds that spread out
over the whole sky.
•They are less than 2km
from the ground and
appears uniformly grey
and dull.

18. Nimbus clouds
•These are the real rain
clouds – thick, dark
and black and spread
out in layers. They
cause continuous rain
or snow.