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 Internet Activity Teacher Notes

Farms in America

Teacher Notes:

• As an extension, have students research other information about agriculture and present their findings in a research report or portfolio.

Procedure for the Activity

Step 1  ordered pairs: (0, 6.2), (10, 5.6), (20, 4.0), (30, 3.0), (40, 2.4), (49, 2.2)
graph:

The graph shows a steady decline in the number of farms.

Step 2  The values for the rate of change represent the average number of farms, in millions that are being lost per year.

 Years Since 1940 Number of Farms (millions) Rate of Change 0 6.2 — 10 5.6 –0.06 20 4.0 –0.16 30 3.0 –0.1 40 2.4 –0.06 49 2.2 –0.02

Step 3  The average of the rate of change values is –0.08. The rate of change using only the ordered pairs (0, 6.2) and (49, 2.2) is approximately –0.08. The values are approximately the same.

Step 4  ordered pairs: (0, 174), (10, 213), (20, 297), (30, 374), (40, 426), (49, 432)
graph:

The graph shows a steady increase in the size of the average farm.

Step 5    The values for the rate of change represent the number of acres by which farms are increasing in size per year.

 Years Since 1940 Average Number of Acres Per Farm Rate of Change 0 174 — 10 213 3.9 20 297 8.4 30 374 7.7 40 426 5.2 49 432 0.6

Step 6  The average of the rate of change values in Step 5 is 5.16. The rate of change using only the ordered pairs (0, 174) and (49, 432) is 5.27. The values are quite close.

Step 7  As the number of farms is declining, the average size of farms is increasing. This could mean that the amount of land used for farming is staying about the same but fewer people are farmers.

Wrapping Up the Activity

See students’ work.

Washington