Investigate Lab Doubling Time
How can you model population growth and use it to consider the impact on natural resources ?
Materials (per pair)
• colored chips
• calculator
Procedure
1. In this lab, you will model exponential growth and consider how increases in human
populations affect supplies of natural resources. Read through the procedure. Then
construct a data table in which you can record the number of individuals in Population A
and Population B over the given time periods. You may use the space provided at the
end of the procedure, or you may use your lab journal or science notebook.
2. Population A begins with 50 individuals. Record this population in your data table.
3. Count out 50 chips to represent Population A in year one.
4. The population grows by 10 percent each year. Calculate the number of individuals in
Population A in year two, Record your answer in your data table. Then add chips to
show the population in year two.
5. Calculate the number of individuals in Population A in years three, four, five, and so on,
until Population A reaches more than 100 individuals. Record your answers in your data
table. (Hint: When necessary, round decimals up or down to get a whole number)
Continue to add chips to show the population in each year.
6. Population B begins with 50 individuals and grows by 20 percent each year, Predict the
number of years it will take Population B to reach more than 100 individuals.
7. Calculate the number of individuals in Population B in years two, three, four, five, and so
on, until Population B reaches more than 100 individuals. Record your answers in your
data table. Use chips to show the population in each year.