JC Geography flashcards
JC Geography · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Divergent plate boundary
- A constructive margin where two plates move apart, allowing magma to rise and form new oceanic crust; marked by mid-ocean ridges, rift valleys and shallow-focus earthquakes.
- Subduction zone
- A convergent boundary where a denser oceanic plate sinks beneath another plate, creating a deep-sea trench, earthquakes and explosive andesitic volcanoes.
- 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 scree.
- Longshore drift
- The movement of sediment along a coast by swash and backwash; sediment travels in the direction of the dominant wave approach, forming spits and bars.
- River discharge
- The volume of water passing a point in a river per unit time, calculated as cross-sectional area multiplied by mean velocity; measured in cubic metres per second.
- Environmental lapse rate
- The rate at which air temperature falls with height in still air, averaging about 6.5 degrees Celsius per 1000 metres in the troposphere.
- Saturated adiabatic lapse rate
- The rate at which rising saturated air cools, about 6 degrees Celsius per 1000 metres, reduced by latent heat released when water vapour condenses.
- Anticyclone
- A high-pressure system with subsiding air, producing clear skies, light winds and stable conditions; in winter it can cause frost and temperature inversions.
- Relief rainfall
- Rainfall caused when moist air is forced to rise over high ground; the air cools, condenses on the windward slope, and the leeward side lies in a rain shadow.
- Coriolis effect
- The apparent deflection of moving air caused by the Earth's rotation; it deflects winds to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
- Urban heat island
- The tendency of urban areas to be warmer than surrounding countryside because of dark surfaces, reduced vegetation, trapped radiation and heat released by human activity.
- Demographic Transition Model
- A five-stage model describing how birth and death rates change as a country develops, from high stationary through expanding stages to low stationary and declining stages.
- Dependency ratio
- The number of people aged under 15 and over 64 expressed as a percentage of the working-age population aged 15 to 64.
- Population pyramid
- A bar graph showing the age and sex structure of a population; a broad base indicates high birth rates and a youthful population.
- Push factor
- A negative condition at a place of origin, such as drought, conflict or unemployment, that encourages people to emigrate to another area.
- Sphere of influence
- The area from which a settlement or service draws its users; it increases with the settlement's size and the rarity of the service provided.
- Concentric zone model
- Burgess's model of urban land use in which a city grows outward in rings from a central business district through residential and commuter zones.
- Quaternary sector
- The part of the economy concerned with knowledge-based activities such as research, information technology, finance and education, typically dominant in highly developed economies.
- Human Development Index
- A composite index combining life expectancy, education (mean and expected years of schooling) and gross national income per capita to measure development.
- Purchasing power parity
- An adjustment to income figures that accounts for differences in the cost of living between countries, allowing fairer comparison of living standards.
- Agglomeration economies
- Cost savings that firms gain by locating close to one another, through shared suppliers, skilled labour pools, infrastructure and information flows.
- Fair trade
- A trading arrangement guaranteeing producers a minimum price, a social premium and long-term contracts, reducing their vulnerability to commodity price swings.
- Brandt line
- A line drawn on world maps dividing the wealthier Global North from the poorer Global South; criticised for oversimplifying inequality within countries.
- Systematic sampling
- A sampling method in which data points are taken at regular intervals, for example every ten metres along a transect, to reduce observer bias.
- River discharge formula
- Discharge equals cross-sectional area multiplied by mean velocity; area is measured in square metres and velocity in metres per second, giving cubic metres per second.
- Infiltration rate
- The speed at which water enters soil, calculated as the volume of water absorbed divided by the time taken, usually expressed in millimetres per minute.
- Environmental quality survey
- A fieldwork technique using an ordinal scale to score features such as litter, noise and graffiti; results are subjective and improve with repeat surveys.
- Six-figure grid reference
- A location reference giving eastings before northings, each to three digits, locating a point on a map to a precision of 100 metres.
- Contour lines
- Lines on a map joining points of equal height above sea level; close spacing indicates steep slopes and wide spacing indicates gentle slopes.
- Vertical exaggeration
- The ratio of the vertical scale to the horizontal scale on a cross-section; a value of 2 means heights are drawn twice as steep as reality.
- Choropleth map
- A map using shades or colours to represent the density of a variable per unit area within defined regions; class intervals must be stated to avoid misinterpretation.
- Map scale 1:50,000
- A ratio scale in which one centimetre on the map represents 50,000 centimetres, or 0.5 kilometres, on the ground.