1. Biology and Geology 3º ESO A

2. Use of water Domestic and urban Bathroom, preparation of food, watering the garden. Washing, drinking, etc. Comsumption FarmingIndustry Water for livestock, cleaning, irrigation, etc. Refrigeration, cleaning of materials, etc

3. Without comsumption Obtaining energy Means of transport RecreationLandscapes resources River transport, transporting crude oil, etc Hydroelectrical-energy Swimming, sailing, fishing, water sports, etc. Rowing boat Conservation of species and natural spaces, etc.

4. Xestión da auga Fresh water is essential for human survival. Fresh water represents just 3% of all the water of the planet: it is an extremely scarce resource. It is very important to manage its use carefully by means of: Hydrological plants. These allow us to optimise water resources. Dams for storing water.Desalination plants for extracting salt Plants for extracting groundwater. However these plants can have a negative effect on the environment and lead to the risk of overexploitation.

5. Saving water Agriculture uses the most amount of water, so it is very important to improve irrigation. It is also important to reduce consumption in the home. Agriculture: water’s biggest consumer

6. Sewage treatment plants Sewage contains a great deal of polluting material. It is important to treat and clean it in water treatment plants, before returning it to the environment.. Fresh water 1. Physical treatment 2. Biological treatment3. Chemical treatment 4. Sludge treatment Sludge is treated to obtain biogas or for agricultural use. Sand, fats. Salts and heavy metals are eliminated Microrganisms descompose organic compounds.

7. Making water potable A number of purification treatments are needed to obtain drinking water or “potable water” which is water of sufficiently quality that it can be consumed safely.

8. The overexploitation of resources The overexploitation of resources produces: The deforestation of large areas and the progressive loss of soil due to erosion. The extinction of species (loss of biodiversity). The exhaustion of geological resources and the contamination and destruction of landscapes as a result of the extraction of these resources. Southern Mexico DeforestationThe extinction of species Exhaustion of oil Oil well in the Gulf of Mexico

9. Greenhouse effect Natural greenhouse effect The greenhouse effect is a natural phenomenon, thanks to which the Earth retains part of the solar radiation and reaches a temperature that makes life on the planet possible. Pollution, together with the progressive lost of forests, leads to greater retention of this radiation, leading to an increase in the temperature of the planet, in other words global warming. 1.Solar radiation hits the Earth’s surface. 2.The Earth reflects part of this solar radiation. 3.Part of the radiation reflected by the Earth is returned to space. 4.Another part of the radiation is absorbed or retained by the atmosphere due to the action of certain gases, such as CO 2 and H 2 O vapour.

10. 1.Solar radiation hits the Earth’s surface. 2.The Earth reflects part of this solar radiation. 3.Part of the radiation reflected by the Earth is returned to space. 4.Pollution, together with the progressive disappearance of forests, causes greater retention of the radiation, which leads to an increase in the temperature of the planet How the increase in the greenhouse effect occurs: CO 2 Increase in natural greenhouse effect

11. The ozone layer filters the ultraviolet rays of the solar radiation (which can cause skin cancers) and prevents the majority of them from reaching the Earth’s surface. The CFCs used in aerosols and refrigeration systems destroy this layer, causing the so-called hole in the ozone layer.

12. Acid rain is rain or snow with higher acidity than normal. Acid rain is generate in several phases: 1)Industry, thermal power plants and vehicles emit polluting gases into the atmosphere (nitrogen and sulphur oxides) generated by the combustion of fossil fuels. 2)These oxides react with water in the atmosphere and turn into nitric and sulphuric acid, which return to the Earth in the form of rain or snow with a high level of acidity. 3)The acid rain destroys the leaves of the trees an acidifies the soil, causing the death of forests and the destruction of lakes. In the cities, it contributes to stone sickness, which destroys limestone or marble monuments.

13. Stone sickness which destroys limestone and marble monuments Death of forests and acidification of the soil.