What caused the change?
Labs / History
Demographic Transition
Every industrializing society passes through the same demographic arc: death rates fall first, birth rates follow, and the age pyramid swells then tips top-heavy. Drag the timeline to scrub Sweden from 1750 onward, or grab the birth & death sliders to sculpt your own pyramid and read off its median age and dependency ratio.
Labs / History / Demographic Transition
Demographic Transition
Every industrializing society passes through the same demographic arc: death rates fall first, birth rates follow, and the age pyramid swells then tips top-heavy. Drag the timeline to scrub Sweden from 1750 onward, or grab the birth & death sliders to sculpt your own pyramid and read off its median age and dependency ratio.
Why it matters
Why explore this?
History is about change over time and the choices that shape it. This model helps you compare causes, consequences, and patterns without treating the past as a list of dates.
Explore
Try the model
Pop 8.0 MMedian 24 yrDependency 70 %Stage 1 · High stationary
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- In Stage 2, death rates have crashed but births stay high. Why does that gap make the pyramid's base explode outward?
- Scrub Sweden slowly. At what decade does the wide triangle start turning into a column, and what changed first — births or deaths?
- Hit Baby boom and watch the amber bulge climb. How many years until that cohort hits retirement age and swells the dependency ratio?
- Push the birth rate below the death rate. What happens to total population and median age when a country enters Stage 5?
- Compare Stage 1 and Stage 4 at the same total population. Which one has to support more dependents per worker, and why?
Explain
Make sense of what happened
Build an explanation with a cause, a change, and a consequence. Then identify evidence from the model and one limitation of what the model can show.
Check
Before you leave
Who or what was affected?
What can this model not tell us?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.