1. What is the atmosphere?The atmosphere is the air which surrounds the Earth.Air is a mixture of gases. It is mainly nitrogen andoxygen. There are also small quantities of carbondioxide, ozone and water vapour.2. The layers of the atmosphere1. 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 phenomenaThe principal weather phenomena are precipitation andwind.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.
1. The hydrosphereAll the water on Earth makes up the hydrosphere. Water isw usually aliquid (sea water), but can appear in solid (ice), gas (clouds)2. The water cicleThe water cycle is the constant circulation of water between de sea, theatmosphere 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.
1 The geosphereThe 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 mineralsRocks 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 andshine.3 Types of rockRocks 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.
1 VolcanoesVolcanoes form in places where there is magma.When a volcano erups, internal forces push the magma up throughacentral pipe, the volcanic chymney. It emerges through a circularopening called a crater. Magma is called lava when it reaches thesurface.2 EarthquakesEarthquakes are caused by movements of Earth´s crust. They candestroy buildings and bridges.Earthquakes in the ocean floor produces enormous, destructivewaves called tsunamis.3 WeatheringThe 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.