PROBLEM: How do you plot and use data on a map?

PREDICTION:

PROCEDURE: Using the maps and soil samples, answer the questions in the following two exercises.

EXERCISE 1: There are many soil types on the Earth. The generalized map of the United States on a following page shows two types of soil pedalfers and pedocal.

1. Define pedalfer, pedocal, and laterite. [Clue: al=aluminum; fe=iron; cal=calcium]
   
   pedalfer:
   
   pedocal:
   
   laterite:
   
     
2. Look at the general soil map of the United States. What is the soil type in each of the following areas?

EXERCISE 2:

MATERIALS: soil samples, magnifying glass

1. Classify each soil sample by color. Call dark soil pedalfers and light soil pedocals. Record the location of each sample, as labeled on the bag
   
   

2. Color the pedocal samples blue and the pedalfers red on the detailed map of San Francisco Bay area.

CONCLUSION: Do you see a pattern of pedocals and pedalfers on the San Francisco Bay area map? 

What is the benefit of a more detailed soil map? Explain your answer