MATSEC SEC Geography cheat sheet

Plate boundaries: divergent (constructive) plates move apart and magma rises, forming mid-ocean ridges and rift valleys; convergent (destructive) plates collide, producing fold mountains, deep ocean trenches and volcanic arcs; transform (conservative) plates slide past each other, generating earthquakes but little volcanism.

Rock cycle: igneous rocks crystallise from magma or lava (basalt is fine-grained extrusive, granite coarse-grained intrusive); sedimentary rocks form by compaction and cementation of deposited sediment (limestone, sandstone); metamorphic rocks form when heat and pressure alter existing rock (marble from limestone, slate from shale).

Weathering and erosion: mechanical weathering includes freeze-thaw and exfoliation; chemical weathering includes carbonation of limestone and oxidation; erosion involves transport by water, wind or ice, whereas weathering is in-situ breakdown with no movement.

River processes: erosion by hydraulic action, abrasion, attrition and solution; transportation by traction, saltation, suspension and solution; deposition occurs when velocity falls. Long profiles show concave shape with steep upper course and gentle lower course.

Coastal landforms: constructive waves (low frequency, strong swash) build beaches; destructive waves (high frequency, strong backwash) erode. Headlands and bays form on discordant coasts; caves, arches, stacks and stumps form on headlands; spits and bars form from longshore drift.

Population: birth rate and death rate are per 1,000 people per year; natural increase = birth rate − death rate; the demographic transition model has five stages linking birth/death rates to development; population pyramids show age-sex structure and dependency ratios.

Settlement and urbanisation: site factors include water supply, defence, bridging point and relief; situation refers to position relative to surrounding features; land-use models (Burgess concentric zone, Hoyt sector) describe urban structure; urbanisation is fastest in low-income countries.

Map skills: a six-figure grid reference gives easting then northing to 100 m precision; a four-figure reference gives 1 km precision; scale 1:50,000 means 1 cm on map = 500 m on ground; contours join points of equal height, and closely spaced contours indicate steep slopes.

Climate and weather: latitude, altitude, distance from sea, ocean currents and prevailing winds control climate; relief rainfall occurs when moist air is forced over high ground, cooling and condensing on the windward side, leaving a rain shadow on the leeward side.

Fieldwork sequence: identify a hypothesis or key question, choose sampling method (random, systematic, stratified), collect primary data, record secondary data, present results in graphs and maps, analyse patterns, evaluate limitations and suggest improvements.

Sampling: systematic sampling uses a fixed interval along a transect (e.g. every 10 m); random sampling uses random numbers or coordinates; stratified sampling samples proportionally within subgroups; larger samples reduce sampling error but increase time cost.

Data types: quantitative data are numerical (discharge, pebble size); qualitative data are descriptive (land-use categories, questionnaire responses); continuous data suit line graphs and scatter graphs; discrete or categorical data suit bar charts and pie charts.

Central tendency and spread: mean = sum of values ÷ number of values; median = middle value when ordered; mode = most frequent value; range = highest − lowest; a large range indicates high dispersion and less reliable averages.

River fieldwork measurements: discharge = cross-sectional area × velocity (Q = A × V, in m³/s); velocity measured with a flow meter or float and timed over a known distance; bedload measured by measuring the long axis of pebbles at sample points.

Beach fieldwork: beach profiles are measured with ranging poles and a tape, recording horizontal distance and vertical drop to calculate gradient; longshore drift direction is tested with a float tracking experiment; sediment size measured by callipers.

Spearman's rank correlation coefficient: rs = 1 − (6Σd²) ÷ (n³ − n); values range from −1 (strong negative) through 0 (no correlation) to +1 (strong positive); significance depends on sample size and critical values table.

Case-study requirement: each case study should state location, key physical or human processes, specific data or named examples, and management responses; for example a named river management scheme should include hard and soft engineering options and their costs and benefits.

Evaluation criteria for fieldwork: reliability (repeatability of measurements), accuracy (closeness to true value), validity (does the data answer the question), and representativeness (does the sample reflect the whole population).