Both of these are bar graphs, and students will need two contrasting color pencils to complete them, such as green and orange.  A ruler or the edge of an index card will help keep the lines straight.  Remind students to use the same color scheme for the graphs on both pages. 

What the Chart Shows

   This graph shows the enormous yield of two important New World crops, corn and the potato, compared to two Old World crops, rice and wheat.  The date, 1992, is 500 years after the first voyage of Columbus.

   Corn and potatoes help feed the world today, and have had a big impact on history as well.  They helped boost the food available to Europeans and Africans after the Age of Discovery.  Ireland's history is, of course, closely tied to the potato crop and its failure in the 19th century.  When the potato blight (a fungus) destroyed the crop there in the 1840s, hundreds of thousands of Irish people immigrated to the United States. 
 
 

   Both of these are bar graphs, and students will need two contrasting color pencils to complete them, such as green and orange.  A ruler or the edge of an index card will help keep the lines straight.  Remind students to use the same color scheme for the graphs on both pages. 

What the Chart Shows

   This graph shows the dollar value of the same four crops listed on the previous page.  Remind students that a billion is a thousand million.  Write the figure for corn on the board:  $ 19,700,000,000. 

   Corn is especially important and valuable to American farmers because it grows well and has many uses.  The crop is used in such familiar products as corn flakes and other cereals, but is also valuable for animal feed and other purposes.  (See the response for the chart question below.) 
 
 

   What reasons can you give...

   Corn is a very high-yield crop, as the first graph shows.  It is also very nutritious, and can be used in a wide variety of ways.  It can be boiled and eaten right on the cob, or the kernels can be ground into flour for use in breakfast cereal or tortilla shells.  Popcorn is a popular snack, of course.

   Corn is also widely used as animal feed, and even for use in making a kind of alcohol added to gasoline.  The additive, called methanol, improves the combustion process and reduces pollution from cars.

   Indians called corn maize, and played a key role in developing the plant into a food crop.  Over the many centuries after they first planted and harvested corn, Indians would have saved seed from plants with the largest largest ears.  As this yearly pattern continued over countless generations, better and better varieties of the plant were grown.

   The process of selection for better varieties has continued on American farms.  For example, corn as it was grown in the 1600s and 1700s was not sweet like the varieties that have been developed since.  Today, the sweet varieties are a regular feature of summer cookouts and picnics.