2. 1. What is the atmosphere?
The atmosphere is the air which surrounds the Earth.
Air is a mixture of gases. It is mainly nitrogen and
oxygen. There are also small quantities of carbon
dioxide, ozone and water vapour.
2. The layers of the atmosphere
1. Troposphere: is the lowest layer. Most gases are in
this layer.
2. Stratosphere: is the next layer.
3. Ozone layer: is a thin layer of ozone in the upper
stratosphere
3. Weather phenomena
The principal weather phenomena are precipitation and
wind.
1. Precipitation: is water, snow or hail.
2. Wind: is is the movement of air, and has different
names depending on how strongly it blows.

3. Sea
clouds
water
Rivers
Rain or
and
snow
lakes

4. 1. The hydrosphere
All the water on Earth makes up the hydrosphere. Water isw usually a
liquid (sea water), but can appear in solid (ice), gas (clouds)
2. The water cicle
The water cycle is the constant circulation of water between de sea, the
atmosphere and land.
1. Liquid water in the sea, rivers and lakes evaporates with the heat of
the sun and becomes water vapour.
2. Water vapour rises and condenses into drops ofr water and form
clouds.
3. Water falls from clouds as rain or snow: precipitation.
4. Water flows over the land and filters into it. It forms rivers and lakes.
Some water comes again to the sea or evaportes.
And the water cycle start again.
3. The movement of water
 Waves are the rise and fall of the water´s surface.
 Tidesare the rise and fall of the sea level twice a day.
 Ocean currents are the movement of large masses of ocean water in
the same direction.

5. 1 The geosphere
The geosphere is made up of three layers:
• The crust is the Earth´s outer layer.
• The mantle is the Earth´s middle layer. It do many hot. In
some parts there is magma.
• The core is the Earth´s innner layer. It also extremely hot.
2 Rocks and minerals
Rocks are natural materials wich make up the Eath´s crust.
Are made up of minerals. Minerals are pure.
We can identify each minerals by its density, colour, hardness and
shine.
3 Types of rock
Rocks can be classified into three types:
• Sedimentary rocks are formaed of pieces of other rocks.
• Igneous rocks are formed when magma cools and solidifies.
• Metamorphic rocks are formed when heat or pressure changes
the original rocks.

7. 1 Volcanoes
Volcanoes form in places where there is magma.
When a volcano erups, internal forces push the magma up througha
central pipe, the volcanic chymney. It emerges through a circular
opening called a crater. Magma is called lava when it reaches the
surface.
2 Earthquakes
Earthquakes are caused by movements of Earth´s crust. They can
destroy buildings and bridges.
Earthquakes in the ocean floor produces enormous, destructive
waves called tsunamis.
3 Weathering
The action of wind and water is called weathering.
• Erosion is the removal of soil and rocks by wind and water.
• Transport is the movement of eroded material.
• Sedimentation the acumulation of eroded material from other
places.