Density is a number, distribution a pattern
Density and distribution differ. Density is a number -- average people per km2 (population / area; e.g. 6,000,000 / 10,000 = 600 per km2). Distribution is the pattern of where people live -- even/uneven, clustered/dispersed -- described using rivers, coasts, mountains, latitude or the tropics. An area is densely populated (a river valley or city) or sparsely populated (a desert, high mountains). Keep the two ideas separate.
Four factor groups shape density
Four factor groups shape density and distribution; name the group plus a mechanism. Physical: relief (flat land beats mountains), climate (rainfall attracts; heat, cold or aridity repels), water, soil, resources. Economic: jobs, industry, ports and trade routes draw people; no work loses them. Social: schools, hospitals, housing. Political: a new capital (Brasilia, Abuja) or conflict. Dense places combine favourable factors, sparse ones the opposite.
Egypt: packed into the Nile, empty desert
Egypt is a reusable case study because the contrast is sharp: about 100 million people, yet ~95% live on ~5% of the land -- the narrow Nile valley and delta. This strip is dense because the Nile gives water for drinking and irrigation, its silt builds fertile soil, the land is flat, and Cairo and Alexandria offer jobs. The Western and Eastern Deserts (Sahara) are sparse -- extreme aridity, high temperatures, no water, infertile sand, few jobs.
Drawn from real examiner reports.
Naming continents, not describing a pattern
Distribution answers that just name places -- "lots of people in Asia" -- miss the required PATTERN. A credit-worthy description gives the shape (even/uneven, clustered) plus reference to coasts, valleys, mountains, or latitude and the tropics (e.g. dense in the tropics near the coast, sparse in the far north). Stating where people are NOT found earns nothing.
Digest (## 1.4): distribution needs an even/uneven, clustered pattern with reference to tropics/latitude, not just naming continents; stating where a feature is NOT found earns no credit (s23 P21 Q5a).
Density vs distribution confused
The key definition trap. Density is a number -- people per km2 (population divided by area). Distribution is a pattern -- WHERE people live, in words. Candidates lose marks giving a pattern answer when asked to calculate density, or a figure when asked to describe the distribution. Match the command word: calculate density wants a number and units; describe wants the pattern.
Sparse areas as a name-list
Asked about sparsely populated areas, weaker answers just list places -- "the Sahara, Siberia, Antarctica" -- without the point that they are sparse BECAUSE of a shared factor (too dry, cold, steep or far from the coast). The mark comes from linking the pattern to a reason with precise language (direction, latitude, distance). Pair each sparse area with its limiting factor.
Digest (## 1.4): for sparsely-populated areas candidates list continents at length without making the actual distributional point (w22 P21 Q2a).
Using only one of two given statistics
When a resource gives two figures -- for example population density AND climate data -- the best answers use BOTH together with correct units, whereas most candidates quote only one. Link them: "the wetter east has over 400 people per km2, while the arid west is below 10." Attach units (people per km2, mm, degC) to every figure.
Digest (## 1.4): the best distribution answers use BOTH given statistics together with correct units; most candidates use only one (s22 P13 Q1a).
Inverting the density formula
Density is always population divided by area, giving people per km2 -- never area divided by population. When population is smaller than area the answer is a decimal below 1 (e.g. 96,000 / 240,000 = 0.4 per km2), tempting candidates to flip the division. A second slip is dropping the units. Keep population on top and write "per km2".
(general exam skill)
Describe vs explain confused
The command word decides the answer. "Describe the distribution" asks WHAT the pattern is (uneven, clustered on the coast), not reasons. "Explain" or "suggest reasons" asks WHY it exists (water, jobs, aridity), not a re-description. Candidates give reasons on a describe question, or a description on an explain one. Match the answer to the command word.
Digest (## Cross-cutting exam technique): command-word neglect -- "describe" answered with explanatory content or vice versa -- is a key message in every report read (s22, w22, s23, w23).
Dense does not mean overpopulated
Density measures people per km2; it says nothing about whether resources can support them. Overpopulation means too many people for its resources, so living standards fall. A city can be densely populated but NOT overpopulated -- wealthy and well-serviced, with jobs, food and water despite thousands per km2. Judge it against resources, not the density figure.
Digest (## Cross-cutting exam technique): vague/unqualified terminology such as "overcrowding" recurs as a credit-blocker; conflating a measured figure with a judgement about resources is a persistent precision error (all four sittings).
7-marker: name a country, link the reasons
The 7-mark density case study rewards located detail and linked reasoning. Name a real country and places within it (Egypt: Nile valley, Cairo, Western Desert), LINK each cause to its effect, and cover BOTH the dense and sparse sides.
Describing a distribution or choropleth
Describe a distribution or choropleth in order: overall pattern first (uneven), then where density is high (river and coast), then where it is low (interior desert), quoting legend figures with units and compass directions (north/south), not "above/below".
Use exact figures, not vague words
Precision earns marks. Replace "about", "nearly" and "majority" (under 50%) with exact figures and units (people per km2, %). When comparing places use comparative words -- higher/lower, denser/sparser -- not bare figures, and follow any data instruction exactly.
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