Name: __________________________________
TOC#
How Big is a Billion?
How many people can Earth hold?
Pre-activity questions
1. Draw and label 3 graphs that show exponential growth, logistic growth, and a graph of what would
happen when you rapidly exceed your carrying capacity (j-curve).
2. Which of these graphs do you think depicts human population growth? Why?
3. How many people do you think are on earth right now?
Background
Currently, the human population on Earth is over 7 billion individuals. But, how big is a billion? How big is 7
billion people? How can you understand such a large number? Today, you will complete several activities to
show what 7 billion people looks like.
Problem 1:
a) What would be the length of a million people holding hands?
b) How about a billion people holding hands?
Process:
1. I would estimate that a million people holding hands would stretch ________ miles. (Are the arms
stretched out or down?)
2. The average estimate for my group is _______ miles.
3. Measure the length of 4 people standing holding hands.
a. The length is ________ cm, or __________ meters.
b. The ratio of people to length is _______ : _______.
______4 people______
Answer to 3a in meters
=
1,000,000 people
x meters
Cross multiply to solve for x. _____________ meters.
4. How many kilometers would the line of one million people be? _____________ km. How many miles
long is this (1 mile - 1.6km)? _____________ miles.
5. How many miles long would a line of one billion people holding hands be? _____________
6. The circumference of the Earth is roughly 25,000 miles. A line of a billion people holding hands would
circle the globe how many times? _____________
7. How many times would this be if it were 7 billion people? ___________________
8. Is this number greater than or less than what you and your group were expecting?
9. Why do you think you over/under estimated? Why?
10. Where you surprised? Why?
Problem 2:
a) Imagine a crowd of a million people. How big a field do you think you would need to
contain them all?
b) How much land would you need to hold a billion people?
Process:
1. If an acre is about the size of a football field, you would need ___________ people to fill it (estimate)
2. Using the number of people you estimated, you would probably need _________ acres to contain one
million people. (Estimate)
3. The average estimate for my group is ____________ acres.
4. Have four students in your group stand together in a cluster. Measure the area of the space in square
meters. They take up _________ square meters
5. Set up a ratio of people to area to find how many square meters (m2) are needed for a million people.
4 people = 1,000,000 people
_____ m2
X m2
Cross multiply to solve for x. ____________________m2
6. If 1 acre = 4,047 square meters (m2), about how big a field would you need to contain one million
people? ___________ acres. Think about how many football fields that is
7. Can you think of an area in your community that is about this size? Look up the populations of San
Francisco and Mill Valley:
8. How many acres of land would you need to contain one billion people? __________ acres.
9. How about 7 billion: _________________
10. Is this number greater than or less than what you and your group were expecting?
11. Why do you think you over/under estimated? Why?
12. Where you surprised? Why?
Conclusion Questions
1. What is your reaction to these two problems in regards to a population of 7 billion people?
2. Watch video clip your teach shows and write down your reaction.
http://video.nationalgeographic.com/video/the-magazine/the-magazine-latest/ngm-7billion/
3. How has the size of the human population changed over time?
4. What do you think will happen if the human population continues to grow this way?
5. Think back to the Population Bomb reading you did a few days ago, is the human population growing
the same in all areas? Why or why not?