MATSEC IM Geography flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Divergent plate boundary

A boundary where two plates move apart, allowing magma to rise. It creates mid-ocean ridges, rift valleys and new oceanic crust, with shallow earthquakes and basaltic volcanism.

Igneous rock formation

Igneous rock forms when molten magma or lava cools and crystallises. Slow cooling underground produces coarse crystals such as granite; rapid cooling at the surface produces fine crystals such as basalt.

Freeze-thaw weathering

A mechanical weathering process in which water enters cracks in rock, freezes and expands, prising the rock apart. Repeated cycles produce angular fragments known as scree on cold, upland slopes.

Longshore drift

The movement of sediment along a coastline in a zigzag pattern. Waves approach obliquely, carrying material up the beach, and the backwash returns it straight down, so sediment gradually travels downwind.

Corrie (cirque)

An armchair-shaped hollow eroded at the head of a glacier by rotational abrasion and plucking. After the ice melts it may fill with water to form a tarn.

Orographic rainfall

Rainfall caused by relief. Moist air is forced to rise over high ground, cools, condenses and precipitates on the windward slope, leaving a drier rain shadow on the leeward side.

River discharge formula

Discharge is the volume of water passing a point per second. It is calculated as cross-sectional area (width × mean depth) multiplied by mean velocity, usually expressed in cubic metres per second.

Demographic Transition Model

A five-stage model describing how birth and death rates change as a country develops. It moves from high stationary rates through falling death rates and falling birth rates to low stationary rates.

Dependency ratio

The number of people aged under 15 and over 64, divided by the number aged 15 to 64, multiplied by 100. It shows how many dependants each working-age person supports.

Push and pull factors

Conditions that drive people away from a place, such as poverty or conflict, and conditions that attract them to another, such as jobs or safety. Together they explain migration flows.

Site and situation

Site is the actual land a settlement occupies, including relief, water and defence. Situation is its position relative to surrounding features such as routes, rivers and other settlements.

Economic sectors

The division of employment into primary extraction, secondary manufacturing, tertiary services and quaternary knowledge work. Development usually shifts the balance from primary towards tertiary activity.

Transnational corporation

A company that operates production, marketing or services in more than one country. It can create jobs and exports in host countries but may also cause dependency and uneven development.

Urban land value

The price of land, which generally falls with distance from the central business district. Competition from commercial users near the centre pushes land values highest there.

Renewable resource

A natural resource that is replenished naturally within a human timescale, such as solar energy, wind, hydro power or biomass. Its use rate must not exceed its rate of renewal to be sustainable.

Enhanced greenhouse effect

The warming caused when human emissions of greenhouse gases trap more outgoing long-wave radiation than the natural greenhouse effect would. It raises global mean temperature and alters climate patterns.

Hazard risk equation

Risk equals hazard multiplied by vulnerability, divided by capacity to cope. It shows that a large hazard need not cause disaster where exposure is low and preparedness is high.

Sustainable development

Development that meets present needs without compromising the ability of future generations to meet theirs. It balances economic growth, social equity and environmental protection.

Ecological footprint

The area of biologically productive land and water needed to supply a population's resources and absorb its waste. It is measured in global hectares and compared with available biocapacity.

Water stress

A condition where demand for water exceeds the amount available, or where poor quality restricts its use. It is measured by comparing water withdrawals with renewable freshwater supply.

Map scale conversion

On a 1:50,000 map one centimetre represents 500 metres on the ground. Multiply the measured map distance by the scale denominator, then convert centimetres to metres or kilometres.

Six-figure grid reference

A precise location given by three digits for the easting and three for the northing. The first two digits locate the grid square; the third digit subdivides it into tenths.

Contour spacing

The distance between adjacent contour lines on a map. Closely spaced contours show steep slopes, widely spaced contours show gentle slopes, and even spacing shows a uniform gradient.

Interquartile range

The difference between the upper and lower quartile of a data set. It describes the spread of the middle half of the values and is less affected by extreme outliers than the range.

Spearman's rank coefficient

A statistical measure of the strength of a monotonic relationship between two ranked variables. Values near plus one or minus one indicate strong correlation; values near zero indicate little relationship.

Choropleth map

A map in which areas are shaded or patterned in proportion to a value such as population density. It shows broad spatial patterns but can hide variation within large areas.

Systematic sampling

Selecting data points at regular intervals along a line or grid, such as every tenth metre along a transect. It is repeatable and detects change across a gradient but can miss periodic features.

Quadrat sampling

A square frame placed on the ground to record vegetation cover, species frequency or abundance. Repeated quadrats allow percentage cover and species richness to be calculated and compared.

Bipolar rating scale

A fieldwork technique recording a judgement on a scale between two opposite descriptors, such as clean to polluted. Fixed criteria and repeat observations reduce observer bias.

Fieldwork hypothesis

A testable statement predicting a relationship between variables, written before data collection. Fieldwork aims, sampling design and statistical tests should all follow from it.

Map symbol interpretation

Reading the key to identify land use, relief, drainage and communications on a topographic map. Comparing old and modern maps reveals changes in settlement, industry and transport.

Anomalous result

A data value that does not fit the general pattern of the results. It should be checked for measurement or recording error before being excluded from analysis.