**Heating and Cooling of Earth's surface**

Question: How do the heating and cooling rates of land and water compare?

Hypothesis: (state your hypothesis - the answer to your question)

Materials:

- one cup partially filled with sand
- one cup partially filled with water
- desk lamp
- 2 digital thermometers

1. Fill one cup with sand.

2. Take the temperature of the sand in the cup

3. Fill another cup with water.

4. Take the temperature of the water in the cup

5. Place both cups under a lamp

6. Take temperature of each every minute.

7. After 15 minutes, turn the lamp off.

8. Continue taking the temperature every minute, until 30 minutes have passed.

GRAPH YOUR RESULTS using a double line graph. Time goes on the X axis and temperature goes on the Y axis.

Discussion: (please note I took out the question about the dark sand vs. the light sand since we only used light sand).

1. Based on your data, which material heated up the fastest and slowest? 2. Based on your data, which material cooled off the fastest and slowest? 3. If you are at the beach in the afternoon, how would the temperature of the sandy beach affect the temperature of the air above it?

4. How would that temperature change affect the density of the air, and what direction would the air move?

5. How did your hypothesis compare to your data?