What is a city?
Do you live in a city? Why do you think we have cities?
Many people think about landmarks, food, or geography when describing a city. However, it is people who decide to call an area a city. People’s decisions shape the future of a city. Yet how often do we consider all these people? How can we understand cities by thinking about people?
Take a moment to clear your mind. Imagine ten people you know. Now imagine one hundred. Can you do it? How about a thousand? A million?
Talk to the other people on this site. Do you know any of them? Where do you all live? Do you all live in a city? Do any of you live near each other? If you don’t know, ask!
City boundaries are not inherent
They are based on many factors, including population.
Population means the number of people in a city or other area. Density means the concentration of people in an area. Pretend the images above are maps of city population density. The orange square has a higher population density than the blue one.
Boundaries are grey areas
All cities are urban areas surrounded by rural ones.
Look at the green maps below. The middle, where more people live, is urban. The outer area, where fewer people live, is rural.
Imagine driving from Seattle to North Bend. There is no clear border around Seattle; the urban area gradually becomes rural. Now imagine driving back to Seattle. The reverse is also true—rural gradually becomes urban.
Urban and rural define each other
Each observer defines them differently.
The maps at right show how different cities can look by their population densities. While all of the maps have the same number of people, they each have different patterns of population density—different relationships of urban to rural. Let’s use the green map as an example:
Each grey circle shows a different way to draw the city boundary. Can you think of other ways?
Picture population density
Where would you draw the city boundaries?
People make cities
People choose city boundaries, and the borders often change.
Drawing the borders of a city can be difficult because cities do not have clear, permanent boundaries. Let’s look at Seattle.
On the left is a map of King County and the City of Seattle. Can you think of reasons why Seattle’s borders are drawn where they are? Compare this map to the one on the right. It is a map of Seattle by population density.
Where would you draw the boundaries? How do people affect the space of a city? How do people affect the area where you live? Talk about it!
How has your neighborhood changed in your lifetime?
A city’s population density changes as people move to or move away from cities. Cities also grow or shrink as a result of births, deaths, and changes in city borders. These changes can have a number of causes, for example: the city’s popularity, changes in available jobs, and natural disasters. Can you think of other causes?
People aren't the only factor used to draw city boundaries. Can you think of others?
Ask other visitors! Then, draw a map of your neighborhood and post it to the time capsule!