Revision lesson 40 minutes

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Revision lesson 40 minutes

  1. 1. Geography GCSE in 40 Minutes Part 1 – Physical Geography
  2. 2. Rivers and Coasts
  3. 3. What processes happen in a river? Erosion Transportation Deposition
  4. 4. How do rivers erode? Hydraulic Action This process involves the force of water against the bed and banks. Abrasion/Corrasion This is the process by which the bed and banks are worn down by the river‟s load. The river throws these particles against the bed and banks, sometimes at high velocity. Attrition Material (the load) carried by the river bump into each other and so are smoothed and broken down into smaller particles. Corrosion/solution This is the chemical action of river water. The acids in the water slowly dissolve the bed and the banks.
  5. 5. How do rivers transport their load? Bedload/ Saltation Solution Bedload/ Traction Suspension Boulders and pebbles are rolled along the river bed at times of high discharge. Sand sized particles are bounced along the river bed by the flow of water. Fine clay and sand particles are carried along within the water even at low discharges. Some minerals dissolve in water such as calcium carbonate. This requires very little energy.
  6. 6. The Long Profile of River
  7. 7. Why do V-shaped valleys occur?
  8. 8. Waterfall formation
  9. 9. Interlocking spurs In the upper course the river does not have a huge amount of energy to erode as it does not have a high discharge and it has to transport large pieces of sediment. When the river meets areas of harder rock that are difficult to erode it winds around them. A series of hills form on either side of the river called spurs. As the river flows around these hills they become interlocked. So, a series of interlocking spurs are often found in the upper course of a river valley.
  10. 10. Erosion
  11. 11. Meander = a bend in a river
  12. 12. Oxbow lakes
  13. 13. Name that landform...
  14. 14. Floodplains and leveés are formed by deposition in times of river flood. The river‟s load is composed of different sized particles. When a river floods it deposits the heaviest of these particles first. The larger particles, often pebble-sized, form the leveés. The sands, silts and clays are similarly sorted with the sands being deposited next, then the silts and finally the lightest clays. Every time the river floods deposition builds up the floodplain. Floodplain formation
  15. 15. What types of delta are there?  arcuate - the land around the river mouth arches out into the sea, the river splits many times on the way to the sea, creating a fan effect.  cuspate - the land around the mouth of the river juts out arrow-like into the sea.  bird's foot - the river splits on the way to the sea, each part of the river juts out into the sea, rather like a bird's foot.
  16. 16. Rivers flood for many reasons. The main reasons are: Precipitation: Frequent cause of flooding = heavy rainfall over days Ground becomes saturated and water runs over surface Most serious flooding usually after short intense storms. Flash floods usually occur after hot summer when ground dry so water can‟t infiltrate the surface. Water held as snow also can cause floods when melts as temp‟ rises Soil/underlying rock: Rocks that let water through – Permeable Rocks that don‟t let water through – Impermeable Surface run-off and flood risk greater when river basin has impermeable soil and underlying rock. Land use: River basins with little vegetation cover = high flood risk Forested basins = low flood risk Human activity: Deforestation (cutting down trees) and urban growth increasing flood risk Bangladesh = increased flood risk due to deforestation in Himalayas Impermeable tarmac surfaces and concrete surfaces are replacing fields and woodland – surface run-off increased The reasons why some rivers flood
  17. 17. The discharge of a river at any point can be plotted on a STORM HYDROGRPH. This shows the rivers response to a single rainfall eventThe soil becomes saturated and overland flow and through flow reach the river and discharge increases. Overland flow arrives first. The time from peak rainfall to peak discharge is the LAG TIME. The discharge starts to fall slowly as water is added from through flow and groundwater flows which are much slower. The base flow supplies the river with water between storms and keeps it flowing in summer.Rainfall is intercepted or infiltrated into the soil moisture store Start of the storm there is a slow rise in discharge, as only a small amount of water falls into the channel
  18. 18. FACTORS WHICH INFLUENCE STORM HYDROGRAPHS VEGETATION COVER This varies seasonally. The type and amount will affect interception and stemflow/throughfall. Overland flow is reduced. Lag time will be increased. ROCK TYPE Impermeable rocks prevent groundwater flow and encourage through flow and overland flow. These rocks will decrease lag time. Permeable rock will have the opposite effect. LAKES & RESERVOIRS These will store floodwater and thus reduce lag time and control river response to heavy rainfall. SOIL TYPE & DEPTH Deep soils store more water, pipes in the soil encourage through flow. Soils with small pore spaces will reduce infiltration and increase overland flow. LAND USE Impermeable surfaces created by urbanisation will reduce infiltration and encourage overland flow. Different types of crops affect interception rates e.g. cereals 7-15%. RAINFALL INTENSITY & DURATION Intense rain will increase overland flow and reduce lag times. Gentle rain over a longer time will allow more infiltration. SLOPES Steep slopes will encourage overland flow and gentle slope will slow run off down. CLIMATE The distribution of rainfall over the year and the temperatures will affect the lag times.
  19. 19. Boscastle Floods 2004 •It has been estimated that the Boscastle valley‟s catchment area exceeds 23 km2, spanning inland to Bodmin Moor where many small rivers spring. •The steep sided valleys that converge down to the sea, known as “flashy catchments”, act as huge funnels and can produce true flash floods after a sudden cloudburst or prolonged heavy rainfall. •During the afternoon of the 16th, an incredible amount of rainwater fell, conservatively estimated to have been over 1422 million litres of rain in just 2 hours, that‟s over 197500 litres falling per second. At its peak, nearly 25mm had been recorded in a 15 minute time span, that‟s over 632000 litres falling per second, the equivalent of 100 tonnes or 21 petrol tanker loads flowing through Boscastle every second! •Consultants HR Wallingford concluded in their technical study that land use changes would have had little impact on the severity of the flooding in the centre of Boscastle.
  20. 20. Destructive waves
  21. 21. Longshore drift Longshore drift is the movement of sediments, usually sand, along a coast parallel to the shoreline. Waves approaching the shore break in a region called the surf zone. They carry sediment up the shore in a white, frothy surge called the swash, and down again in the backwash. When the swash approaches the shore at an angle, it will carry and deposit sediment both up and along the beach, but the backwash, acting under gravity, will always carry and deposit its sediment perpendicular to the shoreline, following the line of the steepest gradient. This produces a zig-zag movement of sediment along the beach known as longshore drift. Generally, the largest particles of beach sediment are found updrift, closer to the sediment source. The smallest sediment particles, those which are most easily picked up and suspended by wave action, are transported further downdrift before again being deposited.
  22. 22. The formation of a coastal spit Spits are long narrow ridges of sand and shingle which project from the coastline into the sea. The formation of a spit begins due to a change in the direction of a coastline - the main source of material building up a spit is from longshore drift which brings material from further down the coast. Where there is a break in the coastline and a slight drop in energy, longshore drift will deposit material at a faster rate than it can be removed and gradually a ridge is built up, projecting outwards into the sea - this continues to grow by the process of longshore drift and the deposition of material. A change in prevailing wind direction often causes the end of spits to become hooked. On the spit itself, sand dunes often form and vegetation colonises (for example Blakeney Point - North Norfolk) Water is trapped behind the spit, creating a low energy zone, as the water begins to stagnate, mud and marshland begins to develop behind the spit. Spits may continue to grow until deposition can no longer occur, for example due to increased depth, or the spit begins to cross the mouth of a river and the water removes the material faster than it can deposited - preventing further build up.
  23. 23. Where is the Dorset coast?
  24. 24. Holderness Location and Background What processes are operating at Holderness? What are the reasons why Holderness is subject to such a rapid rate of erosion? What management strategies have been employed to protect the coastline? Use the video to help fill this in...
  25. 25. Lost villages of Holderness
  26. 26. ECONOMIC DEVELOPMENT Human Geography
  27. 27. Development means improving the economic and social conditions in a country and the quality of life of the people living there. It is more than wealth as it includes such things as happiness and the state of the environment.
  28. 28. Brandt line – N/S divide
  29. 29. Primary, Secondary, Tertiary or Quaternary?
  30. 30. Tasks UK? Nigeria ? Brazil?
  31. 31. Case Study 1 – LEDC, Primary Activity, Copper mining in Zambia
  32. 32. Case Study 2 – MEDC, Tertiary Activity, Cambridge Science Park
  33. 33. 292km
  34. 34. Human Development Index (HDI) HDI is a way of combining different indicators to come up with a more rounded development level for each country. It comprises: • Life expectancy • Education • GDP
  35. 35. The Happy Index
  36. 36. Types of Aid • Bilateral aid This is aid given from one country to another, in the form of money, goods or services. • Multilateral aid This is aid which comes from several different countries - often through international agencies such as the World Bank. • Tied aid is gifts of money, goods or services that come with conditions attached. For example, the recipient country may have to agree to spend the money in particular ways introduce specific economic reforms allow companies from the donor country to set up or sell goods in the recipient country spend the money on goods and services from the donor country. Both bilateral and multilateral aid may be tied in this way. • Non-governmental aid This comes from NGOs such as Save the Children, UNICEF and Oxfam, which provide money and professional support paid for by donations from members of the public across the world. This type of aid is less likely to come with any conditions attached. Tied aid is now illegal in the UK following the UK funding of a hydroelectric dam on the Pergau River in Malaysia in 1991. The Malaysian government bought around £1 billion worth of arms from the UK at the same time.
  37. 37. Short-term or long-term aid? Aid can also be either short-term or long-term. Short-term aid deals with emergencies such as the tsunami that devastated parts of Asia on Boxing Day 2004. Other disasters requiring short-term aid are earthquakes, hurricanes, flooding, drought, and wars. This type of aid brings immediate help to people - flying in food to prevent starvation, tending the injured and sick, and trying to prevent the spread of disease. Long-term aid is required where problems are deep-rooted or cyclical. For example, the climate in some parts of Africa means that drought commonly occurs. This requires long term development to try to prevent water shortages - for example sinking a well and providing a village with a water pump so it can have permanent access to underground water. Of course, many disasters that require short-term aid also need long-term aid - for example, to rebuild houses and work-places that have been destroyed, or to provide seeds to farmers so that food can be grown the following year.
  38. 38. Note down 3 key facts about the graphs
  39. 39. The Pergau Dam, Malaysi a Tied aid is now illegal in the UK following the UK funding of a hydroelectric dam on the Pergau River in Malaysia in 1991. The Malaysian government bought around £1 billion worth of arms from the UK at the same time.
  40. 40. Aid has to be sustainable to be effective
  41. 41. Goats (Tanzania)
  42. 42. Computers (Kenya) Computers for Schools Kenya Computers for Schools Kenya was established as a non-profit organisation to facilitate the productive and sustainable use of computers in education on a national level in Kenya's secondary schools. Since August 2002 Computers for Schools Kenya has installed over 3,000 high-quality, fully refurbished PCs into Kenyan state secondary schools. Computers for Schools Kenya also advises upon and assess the preparedness of each school's infrastructure and provides ongoing timely technical support to recipient schools. Who benefits? The project will ensure an equitable balance of distribution between rural and urban schools, girls and boys institutions and ensure the inclusion of marginalised sectors, and schools for children with disabilities. Over the coming months Computer Aid International (through the generous financial support of a UK trust) will provide 450 professionally refurbished Pentium 4 computers needed for this project.
  43. 43. POPULATION AND SETTLEMENT Human Geography
  44. 44. Population structures The way of presenting population structures is with a population pyramid.
  45. 45. How do population structures differ within countries? The economically active are those people in the 15 to 64 year age group. It is this group of people who usually earn most of the wealth for a region or town. Those outside of this group are referred to as the dependant population. age  = 3 years
  46. 46. Gambia 2010
  47. 47. 2050
  48. 48. UK 2010
  49. 49. Add sketches of the population pyramids at each stage to your DTM
  50. 50. Underpopulation When resources and development could support a larger population without any lowering of living standards
  51. 51. Overpopulation When the number of people exceeds the amount of resources. Symptoms often include malnutrition and starvation, disease and poverty
  52. 52. Optimum population The population is perfect for the amount of resources. This will be different in countries of different developmental stages
  53. 53. Ageing populations
  54. 54. Youthful populations
  55. 55. China‟s one child policy History of the policy? Incentives for having one child Where is China? Penalties for having more than one child Success? Future of the policy Why does China need a one child policy?
  56. 56. Western Europe – Pronatalist policies Much of western Europe is entering stage 5 of the demographic transition model and there are concerns about ageing populations or underpopulated places.
  57. 57. Net emigration
  58. 58. Net immigration
  59. 59. Push and pull Push Pull Crime rates are high Low crime rates No green spaces Open space Poor quality schools Good quality schools Difficult political regime Democracy High unemployment Good jobs and wages
  60. 60. Mexico to USA Why leave Mexico? • Low standard of living • Lack of skilled, well-paid employment • Few opportunities • Lack of education • Poor quality housing • Poor health service Why migrate to the USA? • Many opportunities • High standard of living (one of highest in the world) • Many job opportunities (well-paid jobs) • Education • Excellent health care • Search for the „American Dream‟ • Some characteristics of Mexico and the USA USA Mexico Unemployment 7% 17% People per doctor 400 1800 GDP per capita $52,000 $10,000 School attendance 99% 55%
  61. 61. Factsheet for Counter- urbanisation in the Chew Valley In the past part of the population worked in coal mining, although there are no working mines in the area now. There is still a fairly large agricultural workforce and in light industry or service industries, although many people commute to surrounding cities for work. Chew Valley School 5 A*-C = 70% Bristol Schools 5 A*- C = 35.4% Winford business park takes advantage of the space, access, attractive working environment and the local labour force. Nearby Bristol airport offers easy access to Europe and the US for business and pleasure Ashton Gate park and ride offers easy access to Bristol for commuters
  62. 62. Map of Indonesia
  63. 63. Indonesia‟s internal migration (transmigrati on) Where is Indonesia? What happened when people moved? Context of the case study Negative aspects of the mega rice project Success? Future of the policy Why does Indonesia need a transmigration policy?
  64. 64. Land use change in an old part of the city
  65. 65. Does Bristol match this model of land use change in an old part of a city?
  66. 66. Greenwich Millenium Village (GMV) How is this development sustainable? Future of GMV – can we learn from it? Context statement/ Viewpoints Positives Negatives Basic facts of the development How has land use helped make GMV ecological?
  67. 67. The recent history of shopping in Bristol Local shops The Galleries Cribbs Causeway Cabot Circus
  68. 68. Low order goods (convenience) don‟t travel far, e.g. The Co-op High order goods (consumer) travel further, e.g. The apple shop
  69. 69. Good luck in your exams!

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