SOCIAL STUDIES. Summaries in English.


UNIT 4


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WEATHER AND CLIMATE

THE ATMOSPHERE.
The atmosphere is a layer of gas that surrounds our planet. It is composed of two gases: oxygen and nitrogen.
The atmosphere is responsible for the planet's temperature.
WEATHER AND CLIMATE.


  • Weather is the state of the atmosphere on a particular day or moment. The weather can be sunny, rainy, foggy, stormy ...

  • Climate is the average temperature, rainfall, pressure and wind. To study the climate, weather stations measure the state of the atmosphere for decades. The climate can be Polar, Oceanic, Mediterranean...
TEMPERATURE


It is the heat in the atmosphere. Temperature can be measured with a thermometer. Temperature can be measured in Degrees Celsius (ºC) and Degrees Fahrenheit (ºF).

Temperature depends on:

  • Latitude. The closer to the Equator, the higher the temperature. Temperature descends as we get closer to the Poles.
  • Altitude. Temperature descends 0.6ºC for every 100 meters in elevation. The higher the location the lower the temperature.
  • Distance to the sea. The sea makes the temperature mild. The closer to the sea, the warmer the temperature.


CLIMATE ZONES.

  • TROPICAL.

It is the zone between the Tropic of Cancer and Tropic of Capricorn.

It is hot because the Sun's rays shine directly on this area.
  • TEMPERATE

These are two zones between the tropics and the poles.

  • POLAR


The polar zones are located on both extremes of our planet. It is very cold here (always below freezing) because the Sun's rays shine indirectly on the area.

RAINFALL.

Water falls from the atmosphere to the Earth. It can fall in the form of rain, snow or hail.
Rainfall depends on:

  • Latitude. It rains more often closer to the equator because heat makes water evaporate.
  • Altitude. It rains more often at higher altitudes.
  • The Sea. The humidity caused by the sea produces rainfall.
Rainfall is measured with an instrument called a pluviometer.


ATMOSPHERIC PRESSURE.
Atmospheric pressure is the force of air on a particular point.
Pressure depends on :

  • Altitude. Barometro_2229.jpg
Low zones have more pressure than high zones.
  • Temperature.
Cold air is heavier than hot air.

High pressure zones or anticyclones correspond to dry, stable weather. Low pressure always brings unstable, rainy weather.

Pressure is measured with an instrument called a barometer.

WIND.

Wind is the flow of air and other gases that compose the atmosphere.
There are global and local winds.

Global

Global winds are the types of wind that appear all over the world because of the following reasons:
- The Earth's rotation
- The Earth's movement around the sun
- The round shape of the world.
Local
Local winds are dependant on landforms. A good example is a mountainous area. Wind blows against the mountain and is forced to go up. Because wind usually blows in one direction, the other side of the mountain has very little wind.

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