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Geography · 03 / 06

Population and migration balances

High school foundations · Worked example and 4 exercises with solutions, at your pace.

Need a foundation?Maps and scale: what a map showsRead a map: legend, scale and choices
UnderstandSee an exampleGuided exercise3 progressive challenges

The principle, simply

Population changes through births, deaths, arrivals and departures. Natural change is births minus deaths; net migration is arrivals minus departures in one area and period. Rates use a reference population. Density is a stock per area, not these flows. Age structure affects needs and change.

THE PICTURE TO REMEMBERPopulation and migration balances
  1. 01Same period
  2. 02Births minus deaths
  3. 03Arrivals minus departures
  4. 04Balance and reference population

WORKED EXAMPLE

From principle to reasoning

120 births, 90 deaths, 200 arrivals and 250 departures give +30 natural change, −50 net migration and −20 total. Positive natural change need not mean growth.

Solve a problem in this subject

  1. Choose scale

    Locate the area and compare local, national and global scales; meanings can change with scale.

  2. Read representations

    Check title, legend, unit, date, source and class boundaries. Density and population-count maps answer different questions.

  3. Identify actors and flows

    Connect places, movements, decisions and inequalities with located examples and interpreted data.

  4. Build a synthesis

    Organise a legend by ideas, then select area, line and point symbols. A sketch explains spatial organisation.

YOUR TURN

01 · Try before checking

Natural change +80 and net migration −30: find total change.

One hint

Add balances for the same period.

Reveal and understand the solution

+50, excluding measurement adjustments and boundary changes.

Compare method, conditions and answer; identify the exact part to revisit.

IMPROVE THROUGH PRACTICE

Three additional challenges with solutions

Start with the first challenge. Write your method before opening a hint; use the solution to find the first step that needs work.

Reflect after practising
02 · Recognise and understandLink to this exercise

With 1,200 births and 900 deaths, find natural increase.

A hint to get started

Natural increase excludes migration.

Step-by-step solution
  1. Natural increase = 1,200 − 900.
  2. It is +300 people.
  3. This is not yet total population change.

Which step did you miss? Retry without help, then explain why the method works.

03 · Apply the methodLink to this exercise

Add 500 arrivals and 700 departures to the preceding data. Find total change.

A hint to get started

Add natural increase and net migration.

Step-by-step solution
  1. Net migration = 500 − 700 = −200.
  2. Total change = 300 − 200.
  3. Population rises by 100 people in this simplified balance.

Which step did you miss? Retry without help, then explain why the method works.

04 · Go furtherLink to this exercise

Why can migration not always be reduced to one economic cause?

A hint to get started

Separate departure factors, destination factors and mobility constraints.

Step-by-step solution
  1. Motives may combine work, study, family, safety or environment.
  2. Networks, resources and rules shape trajectories.
  3. Situated analysis avoids assigning one motive to everyone.

Which step did you miss? Retry without help, then explain why the method works.

The trap to avoid

Counts differ from rates. The natural-change lab does not automatically include migration.

Without notes, can you…

  • Explain the principle in your own words?
  • Rebuild the diagram and its connections?
  • Solve the exercise and justify the method?

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