THE ATMOSPHERE

COMPOSITION OF THE ATMOSPHERE

Was the composition of the atmosphere always the same?

• Was there always oxygen in the atmosphere?

• Evolución composición atmósfera

STRUCTURE OF THE ATMOSPHERE

• There are 5 layers:– TROPOSPHERE– STRATOSPHERE– MESOSPHERE– TERMOSPHERE– EXOSPHERE

• Sobre las distintas capas– http://recursostic.educacion.es/secundaria/edad/1esobiologia/1quincena5/1q5_contenidos_2a.htm– Video

• http://www.youtube.com/watch?v=Jv9r7ZCN-DU

• Aurora borealis

• Video aurora borealis

• Video troposphere

• Troposphere– The closest layer to the Earth– Meteorological phenomena take place here– The greenhouse effect– 80% of the gases are in this layer.

• Stratosphere– It contains the ozone layer

• Mesosphere– Falling stars form here

What happens in the..?

• Ionosphere or Termosphere– Aurora borealis and aurora australis (Northern

and Southern lights) are produced here

• Exosphere– The last layer– Very very few air molecules in this layer– No clear boundary between this layer and space

Weather and climate

• Weather:

• is what the forecasters on the TV news predict each day.

Weather conditions include:

• Humidity Amount of water vapour.

• Clouds.

• Precipitacion (rain, snow or hail)

• Temperature (hot or cold air)

• Wind

Atmospheric pressure• The pressure air exerts on a surface.

• Where is it higher, at sea level or at the top of a mountain?

Low and high pressure areas

Air moves from high pressures areas to low pressure areas

• Climate:–  is the average weather in a place over

many years. – While the weather can change in just a few

hours, climate takes hundreds, thousands, even millions of years to change.

Factors affecting climate are:• Latitude. How far North or South a place is

from the equator.

Longitude. The East or west position of a point on the Earth´s surface.

• Video explaining latitude.– http://www.youtube.com/watch?

v=K2b4iInGYq0

• Longitude video– http://www.youtube.com/watch?v=3z-

j6tXcLAk#t=10

• Distance from the sea. Coastal areas have milder weather than inland areas.

• Ocean currents.

• Video Ocean currents– http://www.youtube.com/watch?

v=Hu_Ga0JYFNg

Meteorological instruments• Thermometer:

– measures the air temperature.

• A BAROMETER:– measures air pressure. – It tells you whether or not the pressure is rising or

falling.

– A rising barometer means sunny and dry conditions, while a falling barometer means stormy and wet conditions.

– An Italian scientist named Torricelli built the first barometer in 1643.

• Anemometer– measures wind

speed.

Weather vane/ Wind vane:

– determines the direction from which the wind is blowing.

• Hygrometer– measures the water

vapor content of air.– The humidity.

• Pluviometer– the amount of rain that

has fallen over a specific time period.

What is atmospheric pressure?

• Video instrumentos meteorológicos– http://recursostic.educacion.es/secundaria/ed

ad/1esobiologia/1quincena5/1q5_contenidos_3d.htm

• Animation