Navigation
Learning how to calculate and interpret population density to understand the pressure on land and resources.
If the entire world's population stood shoulder-to-shoulder, we could all fit inside the city of Los Angeles. So why does the world feel so crowded?
To understand how 'crowded' a place is, geographers use Arithmetic Density. This is the simplest way to measure population pressure. It is the total number of people divided by the total land area. It tells us the average number of people living in a square kilometer or mile. While it doesn't tell us exactly where people live, it gives us a starting point to compare different countries or cities. The formula is:
Quick Check
If a city has 10,000 people and covers 10 square kilometers, what is its arithmetic density?
Answer
1,000 people per square kilometer.
Arithmetic density can be misleading. Imagine a country that is uninhabitable desert. The arithmetic density would look low, but the people are actually crammed into the small green areas. To fix this, we use Physiological Density. This is the number of people per unit of arable land (land suitable for agriculture). A high physiological density means a country has many people relying on a small amount of farmland, which puts massive pressure on food resources.
Quick Check
Which measurement better shows the pressure on a country's food supply?
Answer
Physiological Density.
Even with two types of density, we still face a problem: Population Distribution. Density is just an average. It doesn't tell us about the quality of life, wealth, or infrastructure. For example, a wealthy city with high-rise apartments might have the same density as a crowded slum, but the living conditions are completely different. Geographers must look beyond the numbers to see how resources like water, electricity, and housing are distributed among the population.
Consider two regions with a density of people per . 1. Region A: A modern urban center with -story buildings and advanced plumbing. 2. Region B: A rural farming village with single-story huts and limited well water. 3. The Challenge: While the 'math' of density is the same, Region B faces much higher 'resource stress' because its infrastructure cannot support the population as efficiently as Region A's vertical housing.
What is the formula for Arithmetic Density?
If a country has a very high physiological density but a low arithmetic density, what is likely true?
Two cities with the exact same population density will always have the same standard of living.
Review Tomorrow
In 24 hours, try to explain the difference between 'total land' and 'arable land' to someone else without looking at your notes.
Practice Activity
Find the population and land area of your home province or state online. Calculate its arithmetic density using the formula .