Population and demography — Sociology, 11–13 years
How sociologists describe populations by size, age, births, deaths and movement from one place to another.
What demography is
Demography is the study of how a population is made up and how it changes over time. It looks at numbers such as age, births, deaths and migration, but the numbers describe real people and their lives. A population can mean the people in a town, country or other clearly chosen place.
Why study it?
Communities need to know who lives there before planning schools, buses, homes or health services. Demography grew from the need to count people and understand births, deaths and movement. Numbers do not tell the whole story, but they reveal patterns that one person’s experience cannot show.
A worked example
A village has 1,000 residents. During one year, 25 babies are born, 10 people die, 40 move in and 15 move away. The natural change is 25 minus 10, or 15 people. Migration adds 40 minus 15, or 25, so the population grows by 40 and reaches 1,040.
The common trap
A common mistake is to hear that a population grew and assume that more babies were born. That is reasonable because births are an easy change to notice. Growth can also come from people moving in, while a population may have many births and still shrink if deaths and departures are greater.
Where it appears
Demographic information helps decide where to build classrooms, how many buses a town needs and how services can support an ageing population. It also helps explain why a neighbourhood changes when many people arrive or leave. Good conclusions require careful data, because a total alone does not show people’s reasons or experiences.
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