How Big is Big?

How big is big?

This whole-class exercise helps students understand populations density and spacial relations in understandable, comparable terms. Students, with some classroom tools, will learn about Japanese population density; Chinese population growth; and hypothesize about Mexican immigration statistics. Through this activity, students will:

  • Visualize approximate and relative sizes of the world's regions and populations.
  • Use comparison and analogies to gain a clearer understanding of the world in which they live.

Early anthropologists sometimes characterized tribes by their ability to deal with abstractions. I was amused by accounts of languages that, in dealing with numbers, had only "1, 2, 3, many" until I tried to help students visualize the landscapes, populations, and land-use problems in regions we were studying. This led to the "three chair game."

At 50,000 square miles per chair, three chairs represented the approximate area of California or Japan. With students representing 10 million people each, two students provided the population of California (at that time!). There was plenty of room for them on the three chairs. Eight or nine students had to sit on each other's laps to show the population of Japan (again, at that time). The ones on the bottom really grasped the concept of population pressure! If you are teaching about population and resources over time, it would be enlightening for the students to use this exercise to see how population now differed from when their grandparents were growing up. The same comparison, on a different scale, could be made of the United States and China.

But as a student reminded me after a visit to Japan, not all of any country is as densely populated as the game implies; huge areas of Japan are as sparsely populated as Montana. At this point, the "three chair game" became the "twelve chair game."

This activity is based on the following premises: (1) Students can understand any concepts or data presented in terms of their own experience; (2) Abstractions are meaningful only to their makers; and (3) All learning is by comparison—finding a connection between something known and something unknown. (Please note that, to make conceptualization easier, all numbers in this activity are approximations.)

  1. When beginning the study of a region and its people, initial questions to ask students include "where?" "how big?" and "how many?" After locating the region (preferably on a globe so that its relative size and relationships with other regions are not distorted), ask for area and population estimates—in the case of this activity, for Japan and Montana (Montana is the closest of the states to Japan in area--each is approximately 146,000 square miles—but is radically different in almost every other way). Accept all guesses.
  2. Now, have students look up figures in a recent world almanac or on the Internet. If one chair = 12,500 square miles, about how many chairs would be needed to represent Montana or Japan? (12. Therefore, set out 12 chairs.) Have them calculate larger areas, such as regions, using a 16" globe (on the surface of which 500 miles = 1 inch) and a flexible ruler.
  3. Next, explain that forested mountains, too steep for farming or easy logging, make up 2/3 of Japan's landscape (overturn 8 chairs); dry grasslands, 1/24, and beaches and dunes, 1/24 (overturn 1 chair); over 3,000 tiny, mostly uninhabited islands, 1/24, and thin, poor soils eroded by short, torrential rivers, 1/24 (overturn 1 more chair). The remaining 1/6 (2 chairs) is suitable for agriculture but is increasingly urban (nearly 1/2 of Japan's population is concentrated in the Tokyo, Nagoya, and Osaka areas).
  4. What about Montana's 12 chairs? The partly forested Rocky Mountains run through the western 1/3 (overturn 4 chairs), leveling out into dry grasslands (2 chairs) and grasslands watered well enough for grazing (overturn 4 chairs), leaving, like Japan, 1/6 (2 chairs) for cropland.
  5. Students can use classroom or library resources to calculate the number of chairs that should be overturned for the landscapes of other regions. Start with your school's state (3-way comparisons are preferable to 2-way because they avoid "we-they" polarization).
  6. What about population? If one student represents one million people, how many will represent the population of Montana? (Barely one in 2006). Japan's population? (127 students based on 2006 figures). With two chairs, one student has a choice of seats, but 127 students on two chairs is pretty severe crowding, even with Board of Education mandated class sizes!
  7. Stress to students that unlike area, which remains constant (although some internal categories may change with good or poor land management), populations are constantly changing. Therefore, population numbers always must be qualified by dates. In the last 40 years, Japan's population has increased by half and Montana's by a fourth.
  8. Population, like interest on savings accounts, increases geometrically. Teach your students the Rule of 70: anything increasing at the rate of 1% will double in 70 years; 2%, 35 years. See the Population Reference Bureau figures for the world's countries. Note that some African countries have growth rates of nearly 4%; their populations will double in less than 20 years. Can students see the reasons for China's campaign to persuade families to limit themselves to one child? With their calculators and the Population Reference Bureau website estimates of rate of increase, students can make projections for various regions. Have them calculate Mexico's increase and consider its potential effect on immigration statistics.
  9. Back to area. Montana has about 28,000 square miles of cropland, Japan about 24,000. But, we are accustomed to think of farmland in terms of acres. How many acres are in a square mile? (640). Acres of farmland for Montana? (17,920,000). For Japan? (15,360,000). But how big is an acre? On looking it up, students find that it is 43,500 square feet. Not much help. Can they visualize a football field? How many square feet? (160 x 300 = 48,000). Each Montanan can enjoy-or export-the crops that could be grown on 22 football fields! What about the Japanese? (.122 acre=78 square feet). Have the students mark an 8 x 10 foot rectangle on the classroom floor to help them visualize this area figure.

Author: Elgin Heinz

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