Weather & Climate. 1ºESO. Social Sciences. Sin intenciones comerciales.

1. UNIT 5
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Weather and Climates

2. 1º ESO
Social Sciences

3. Introduction

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 The weather and climate are affected by
atmospheric phenomena (temperature, humidity,
precipitation, atmospheric pressure and wind).
 Weather and climate are different:
 The weather describes the atmospheric conditions
in a particular time.
 Climate refers to atmospheric conditions that exist
in a region over a long period of time.

5. 1.
Atmosphere

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 The atmosphere is a
gaseous layer more than
1000 Km thick that
surrounds the Earth and
that serves to:
 Prevent the Sun’s rays from
directly reaching the Earth’s
surface.
 Protect the Earth against
falling meteorites.

7. Ozone layer
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 The atmosphere’s
function as a filter of
solar radiation is due to
the ozone layer:
 It is located at an
altitude of between 30
and 50 km.
 It prevents ultraviolet
radiation, which is very
harmful to living things,
from reaching the
Earth’s surface.

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 The atmosphere is made up of four layers:
 Troposphere: the closest layer to the Earth,
where meteorological phenomena happen.
 Stratosphere: this layer is made up of various
other layers, such as the ozone layer, and is very
stable.
 Mesosphere: in this layer, the air is very dense.
 Thermosphere: in this layer, temperatures are
very high.

9. Atomosphere
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10. 2.
Temperature

11. Atmospheric Temperature
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 Atmospheric
temperature represents
the degree to which
solar radiation warms
the air.
 The Sun’s rays are
transformed into heat
when they reach the
surface of the planet.

12. Thermometers and Isotherms
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 Temperature is
measured in
degrees centigrade
by
thermometers,
and it is
represented on
maps by imaginary
lines known as
isotherms.

13. Factors
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 Factors that cause a variation in temperature include:
 The latitude or distance from the equator.
 The altitude in relation to sea level.
 Distance from the sea.

14. Latitude
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 As the Sun’s rays fall
perpendicularly
on the equator,
the further from the
equator, the lower
the temperature
becomes.

15. Altitude
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 The higher the
altitude, the less
dense the air is
and the less
ability it has to
retain heat.
 Thus, the higher
we go, the colder
the temperature.

16. Distance from the sea
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 The sea regulates the
temperature because it
takes a long time to
warm up or to cool
down.

17. Distance from the sea
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18. 3.
Air Humidity and Precipitation

19. Humidity
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 Humidity is the amount
of water vapour in the
air from the Earth’s
waters and living things.
 Humidity is measured
using a hygrometer
and the result is
expressed as a
percentage.

20. Relative Humidity
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 The amount of water
vapour that the air can
absorb depends on its
temperature (warm air
absorbs more vapour than
cold air).

21. Precipitation
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 Water vapour causes
precipitation, which is
measured in L/m2 using a
rain gauge.

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 As air rises, water vapour
grows cold and
condenses into small
droplets that form
clouds.
 If the air continues to
rise, the water droplets
begin to stick to each
other, thus growing in
size, until they fall to
Earth in the form of rain.

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 If the air temperature
is very low, the
droplets are
transformed into
snowflakes.
 Hail forms when ice
crystals in the clouds
grow in size and fall to
Earth.

24. 4.
Atmospheric Pressure
and Wind

25. Atmospheric Pressure
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 Atmospheric
pressure is the
weight or force of
the air on the
Earth’s surface.
 It is measured in
hectopascals
using a
barometer.

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 Atmospheric pressure depends on:
a) Altitude: the higher the altitude, the lower the pressure.
b) Air temperature: when warm, air weighs less and rises,
producing low pressure areas and depressions. When cold,
air weighs more and falls, causing high pressure areas and
anticyclones.

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c) The wind: is a mass of moving air that is produced
between two areas of different atmospheric
pressure.
 There are different types of wind, depending on the
difference in atmospheric pressure that produces them.
 Some winds are constant, such as prevailing winds, and some
winds are seasonal.

28. Meteorological Station
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29. Instruments and units of measurement used to measure the
following atmospheric phenomena
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