Geography Form 3

Contents

1. 1. Structure of the Earth

   1 tests 15 questions

   Topic lessons

   • The Earth's interior: crust, mantle and core
   • Rocks and how they are formed
   • The rock cycle and the importance of rocks
   • Plate tectonics: the moving crust
   • Summary

   The internal structure of the Earth The Earth has a radius of about 6,370 km. Scientists cannot dig to its centre, so they learn about its inside mainly from earthquake (seismic) waves , which change speed and direction when they pass through materials of different density, and from volcanic material and mines. The…

2. 2. Forces Which Affect the Structure of the Earth

   1 tests 17 questions

   Topic lessons

   • Internal and external forces, and folding
   • Faulting and its landforms
   • Vulcanicity and earthquakes
   • Weathering and mass wasting
   • The work of running water
   • The work of wind, ice and sea waves
   • Summary

   Internal and external forces The surface of the Earth is shaped by two groups of forces. Internal (endogenic) forces act from inside the Earth and tend to build up relief: earth movements, folding, faulting, vulcanicity and earthquakes. External (exogenic) forces act on the surface and tend to wear the land down:…

3. 3. Soil

   1 tests 16 questions

   Topic lessons

   • Meaning and components of soil
   • How soil is formed
   • The soil profile
   • Properties of soil
   • Types of soils
   • Soil erosion and soil conservation
   • Summary

   Meaning of soil Soil is the thin, loose top layer of the Earth's surface in which plants grow. It is formed from weathered rock mixed with organic matter, water, air and living organisms. Soil forms very slowly – it can take hundreds of years to form a few centimetres – so it must be protected. Components of soil A…

4. 4. Map Reading and Interpretation

   1 tests 17 questions

   Topic lessons

   • Topographical maps, conventional signs and scale
   • Methods of showing relief
   • Recognising landforms from contours
   • Gradient, cross-sections and intervisibility
   • Grid references, bearings and area
   • Interpreting drainage, settlement and human activities
   • Summary

   Topographical maps Map reading is the ability to understand the information shown on a map; interpretation is explaining the relationships between features, such as why settlements are found in a certain place. Topographical maps (e.g. Tanzanian sheets at 1:50,000) show relief, drainage, vegetation, settlements,…

5. 5. Photograph Reading and Interpretation

   1 tests 16 questions

   Topic lessons

   • Photographs in geography and their types
   • Reading a photograph
   • Interpreting photographs
   • Scale of photographs, sketching and the uses of photographs
   • Summary

   Photographs in geography A photograph is a picture of objects or a landscape recorded by a camera. In geography photographs help us observe landforms, vegetation, settlement and economic activities, especially of places we cannot visit. Photograph reading is identifying what is shown; photograph interpretation is…

6. 6. Statistics

   1 tests 17 questions

   Topic lessons

   • Statistics and types of data
   • Line graphs, bar graphs and climate graphs
   • Pie charts and divided rectangles
   • Showing data on maps
   • Mean, median, mode, range and percentages
   • Summary

   Statistics in geography Statistics is the collection, organisation, presentation, analysis and interpretation of numerical data. Geographers use statistics to describe things such as rainfall, population, crop production and trade. Types of data Primary data – collected directly by the researcher (observation,…

7. 7. Map Making and Elementary Surveying

   1 tests 17 questions

   Topic lessons

   • Surveying, types of survey and plotting scales
   • Chain survey: principles and field procedure
   • Booking and plotting a chain survey
   • Prismatic compass survey
   • Plane table survey and levelling
   • Summary

   Meaning of surveying Surveying is the accurate measurement of distances, directions (angles) and heights of points on the Earth's surface, and recording them so that a map or plan can be drawn to scale. Map making (cartography) is drawing the map from the survey data. Surveys are used for planning towns, roads, farms,…