Geography

• Volcanoes and earthquakes are near plate margins
• Fold mountains are near plate margins
• Plates sit on top of the mantle. They move very slowly. This is caused by convection currents in the mantle
• Constructive plate boundaries are when two plates diverge (move apart).
• Destructive plate boundaries are where two plates converge (move towards each other)
• Conservative plate boundary is where two plates slide past eachother.
• Earthquakes occur at destructive or conservative plate boundaries
• As two plates move towards each other one can be pushed down under the mantle. If the plate gets stuck it causes a lot of strain on surrounding rock. Sideways moving plates can also get stuck. When the tension is released it creates seismic waves. This is an earthquake.
• The richter scale measures an earthquakes magnitude. This is measured on a seisometer.
• Monitoring can help predict when hazards are going to happen
• Burning coal, oil and natural gas in power stations gives off sulphur dioxide gas
• Burning oil and petrol in vehicle engines gives off nitrogen oxides as gases. These gases mix with water vapour in the atmosphere, producing weak solutions of sulphuric and nitric acids- acid rain
• Leaves and tree roots can die from acid rain
• High acid levels make rivers and lakes unsuitable for fish
• Acid rain increases soil leaching which removes nutrients from soils
• Acid rain dissolves stonework and mortar of buildings
• Often acid rain doesn't fall where the gases are produced
• Sulphur dioxide can be removed from power station chimneys but the process is expensive
• If demand for electricity is reduced less sulphur dioxide will be produced
• Fitting catalytic converters in cars removes oxides of nitrogen
• Limiting numbers of road vehicles and increasing public transport would cut down on exhaust gas emissions
• Global warming is caused by increased fossil fuel use
• Since the industrial revolution people have needed more energy for work and in the home- this energy has come from burning fossil fuels
• The burning contributes to the greenhouse effect
• Energy from the sun passes through the atmosphere as light and warms up the earth. When the energy is reflected back off the surface as heat it is trapped by greenhouse gases
• Our oceans absorb about a quarter of the carbon dioxide that humans produce by burning fossil fuels. This is changing their basic chemistry. This means that sea creatures that have calcium carbonate in their shells and skeletons cannot grow and develop properly. The more acidic waters are a barrier to the survival of many species
• Some fish are affected by ocean acidification too. Studies show that clownfish in acidic water cannot sense predators effectively and that sharks are hunting prey less effectively.