GCE O/L Geography cheat sheet

Earth's interior layers: crust (5–70 km thick), mantle (to ~2,900 km), outer core (liquid iron-nickel), inner core (solid).

Crust types: continental crust is thick (30–70 km) and granitic (less dense); oceanic crust is thin (5–10 km) and basaltic (denser).

Plate boundaries: divergent (plates move apart, mid-ocean ridges, rift valleys), convergent (plates collide, fold mountains, trenches, volcanoes), transform (plates slide past, earthquakes).

Constructive (divergent) boundary produces new crust; destructive (convergent) boundary destroys crust through subduction.

Rock cycle: igneous (cooled magma/lava), sedimentary (deposited and compacted layers), metamorphic (heat and pressure alter existing rock).

Igneous rock examples: granite (intrusive, coarse crystals), basalt (extrusive, fine crystals). Sedimentary: limestone, sandstone, chalk. Metamorphic: marble from limestone, slate from shale.

Weathering types: mechanical/physical (freeze-thaw, exfoliation), chemical (carbonation dissolving limestone), biological (root action). Erosion moves weathered material; weathering does not.

Landforms by process: river (V-shaped valley, waterfall, meander, oxbow lake, delta), glacial (U-shaped valley, corrie, moraine, hanging valley), coastal (cliff, wave-cut platform, spit, stack).

Weather is the short-term state of the atmosphere; climate is the long-term average (usually 30 years) of weather conditions.

Temperature falls with altitude at roughly 6.5 °C per 1,000 m (environmental lapse rate).

Relief rainfall: moist air forced up a mountain cools, condenses and rains on the windward slope; the leeward side is a rain shadow (dry).

Convectional rainfall: intense heating causes warm air to rise rapidly, forming tall cumulonimbus clouds and heavy showers, common in the tropics.

Frontal rainfall: warm air meets cold air at a front; warm air rises over cold air, producing prolonged rain typical of mid-latitudes.

Climate controls: latitude (angle of sun), altitude, distance from the sea (continentality), ocean currents, prevailing winds, relief.

Ecosystem components: producers (plants), consumers (herbivores, carnivores), decomposers; energy flows through food chains and webs; nutrients are recycled.

Biomes linked to climate: tropical rainforest (hot, wet all year), savanna (wet and dry seasons), desert (very dry), tundra (cold, short growing season), temperate deciduous forest.

Birth rate = births per 1,000 people per year; death rate = deaths per 1,000 per year; natural increase = birth rate − death rate.

Population growth rate includes migration: (births − deaths) + (immigration − emigration), usually expressed per 1,000.

Population pyramid shapes: wide base and narrow top = high birth rate, high death rate, youthful population; narrow base = ageing population, low birth rate.

Dependency ratio = (population under 15 + over 64) ÷ working-age population (15–64) × 100.

Push factors drive people from a place (war, famine, unemployment); pull factors attract them (jobs, safety, services).

Site factors for settlement: water supply, flat land, fertile soil, defence, fuel, bridging point. Situation factors relate to surrounding routes and resources.

Settlement hierarchy: hamlet → village → town → city → conurbation; higher-order settlements are fewer, larger and offer more specialised services with larger sphere of influence.

Urbanisation is the rising proportion of people living in towns and cities; causes include rural-to-urban migration and natural increase.

Economic sectors: primary (extracting raw materials), secondary (manufacturing), tertiary (services), quaternary (knowledge and research).

Agriculture types: subsistence (produce for own use) vs commercial (sold for profit); intensive (high inputs per area) vs extensive (low inputs per area).

Factors affecting farming: climate, soil, relief, market access, capital, technology, government policy.

Industrial location factors: raw materials, power, labour, transport, market, capital, government incentives.

Industry classifications: heavy industry (large, bulky inputs), light industry (smaller consumer goods), footloose industry (not tied to raw material or market).

Energy resources: renewable (solar, wind, hydro, tidal, geothermal, biomass) vs non-renewable (coal, oil, natural gas, nuclear fuel).

Tourism growth factors: rising incomes, more leisure time, cheaper transport, advertising, improved accessibility.

Tourism impacts: economic (income, jobs, foreign exchange), social (cultural change), environmental (footpath erosion, pollution, habitat damage).

Renewable resources can be replenished naturally within a human lifetime (timber, fish, solar); non-renewable resources are finite (fossil fuels, minerals).

Sustainable development meets present needs without compromising the ability of future generations to meet theirs.

Development indicators: GDP per capita, life expectancy, literacy rate, infant mortality rate, HDI (combines income, education and health).

Limitations of GDP: ignores income distribution, unpaid work and environmental costs; HDI gives a broader picture.

The development gap is the difference in wealth and well-being between more and less developed countries; causes include colonial history, debt, conflict, poor climate and lack of resources.

Appropriate technology is low-cost, locally repairable technology suited to local skills and resources (e.g. solar panels, hand pumps, fuel-efficient stoves).

Resource management strategies: reduce, reuse, recycle; water management (dams, desalination, conservation); energy efficiency.

Sustainable tourism practices: limiting visitor numbers, protecting habitats, supporting local business, using renewable energy.

Map scale: 1:50,000 means 1 cm on the map = 50,000 cm (500 m) on the ground; 1:25,000 means 1 cm = 250 m.

Grid references: four-figure gives a square (eastings then northings); six-figure gives a point within the square.

Contour lines join points of equal height; closely spaced contours indicate steep slopes, widely spaced contours indicate gentle slopes.

Cross-sections: plot distance along the horizontal axis and height on the vertical axis, using contour heights along the line.

Climate graphs: bar chart for monthly rainfall and line graph for monthly temperature plotted on the same axes.

Scatter graphs show correlation between two variables; a line of best fit summarises the trend (positive, negative or no correlation).

Mean = total ÷ number of values; median = middle value when ordered; mode = most frequent value.

Photograph interpretation: identify foreground, middle ground and background; use shadows for sun direction; compare with map features for location.

Enquiry sequence: identify question → form hypothesis → collect data → present data → analyse → conclude → evaluate.

Sampling methods: random (unbiased, e.g. random grid points), systematic (regular intervals, e.g. every 10 m along a transect), stratified (proportional to sub-groups).

Larger sample sizes increase reliability; repeat measurements reduce the effect of anomalies.

Data types: quantitative (numerical) vs qualitative (descriptive); primary (collected first-hand) vs secondary (from existing sources).

Presentation choices: bar chart for discrete categories, histogram for continuous data, pie chart for proportions, scatter graph for correlation, choropleth for area data.

Measuring river characteristics: velocity with a flow meter or float, width with a tape, depth with a ruler, discharge = cross-sectional area × velocity.

Fieldwork risk management: identify hazards (water, weather, traffic), use appropriate clothing and equipment, inform a responsible adult, work in pairs.

Evaluation should address accuracy, reliability, limitations and improvements (e.g. more sample points, better equipment, repeat readings).