# Solar Radiation - Sand, Soil, and Water Lab

Solar Radiation - Sand, Soil, and Water Lab

Rationale:

Approximately 70 percent of Earth’s surface is covered by water. The unequal rates of the heating of land and water cause temperature conditions, which significantly affect local and worldwide weather patterns.

Objective: Describe the comparative rates at which water and land surfaces heat and cool.

Procedure

1. Fill 3 beakers with an equal amount (100 ml) of sand, water, and dark soil.
2. Place a probe in each of the beakers at the same depth.
3. Answer the predict questions below.
4. Turn on heat lamp and place beakers directly under the heat lamp.
5. Record the temperature of each substance for 10 minutes at 2 minute intervals in the data table below.
6. Turn the heat lamp off.
7. Record the temperature of each substance for 10 minutes at 2 minute intervals in the data table below.

Predict the following (what do you think is going to happen?)

After sitting ten minutes under the heat lamp:

1. What substance will have the highest temperature? ______
2. What substance will have the lowest temperature? ______

After given ten minutes to cool down (heat lamp turned off):

1. What substance will have the highest temperature? ______
2. What substance will have the lowest temperature? ______

Questions: After completing the graph, answer the following questions in complete sentences.

1. How did the heat energy received by the cup of soil compare to the heat energy received by the cup of water?
1. Refer to your graph, compare the rate of heating and cooling of the soil and water tested.
1. Which is a better absorber and radiator of heat energy, soil or water?
1. A. By 3:00 p.m. on a summer day would air be cooler over ocean water or would it be cooler over the nearby land?

1. Referring to Question 4, how would the density of the air over the ocean compare to the density of air over the nearby land?
1. Refer to the diagram below.

Why does the heat equator for January bend farther into the Southern Hemisphere over the continents of South America and Africa than it bends over the ocean areas?

Key:

Earth’s Heat Equator

January Heat equator ......

July heat equator ______

1. Refer to the same diagram above.

Why does the heat equator move farther into the Northern Hemisphere in July than it moves into Southern Hemisphere in January?

1. List the sources of error from the lab and tell how each error specifically affects your results.
1. Conclusion: How do water and land surfaces differ in their abilities to absorb and radiate heat energy?