# How Do You Store Heat Energy?

Solar energy from the sun is absorbed and reflected differently by Earth’s surface and atmosphere. Because of this, materials that reflect heat better will tend to be cooler, while those that do not reflect heat as well tend to be warmer. In other words, a good reflector of heat is a poor absorber, and a poor absorber of heat is a good reflector. Absorbed solar energy from an object becomes heat energy that is radiated into space. For example, on a sand dune solar energy is absorbed and reflected by the sand during the day. The air above the sand is warm as absorbed solar energy is re-radiated by the sand as heat, warming the air by conduction. At night time the sand continues to radiate heat into space, until the sand becomes quite cool at its surface.

During this investigation you will compare the cooling and heating rates of several different materials such as sand, water, rock and dirt. You do not have to limit your experiment to these materials. Try different colors of dirt and rock. Make sure to use the same amount each time.

Materials:

• Five glass beakers or cups
• Water
• White sand
• Red sand
• Rock chips
• Dirt
• Lamp

Safety concerns: Be sure to keep all electrical, and glassware safety rules. As with all science lab activities, the most important safety rule is to follow all teacher directions.

Procedure:

1. In each beaker place the same amount room temperature tap water, white sand, red sand, rock chips, and dirt.
2. Place the beakers beneath a lamp.
3. Place a thermometer in each of the beakers and record the temperature of each every three minutes for 15 minutes. Record data in the table provided.
4. Leave the thermometers in the containers and move them away from the lamp.
5. Read the temperature of each container every three minutes for 15 minutes and record the data in the same table.
6. Make a graph of your findings and then answer the questions provided.

Analysis:

1. Which of the materials had the highest temperature after 15 minutes?
2. Which of the materials had the lowest temperature after 15 minutes?
3. Which of the materials showed the greatest temperature difference between heating and cooling?
4. Which of the materials showed the least temperature difference between heating and cooling?
5. What happened to the temperatures of each material while the light was on? Explain your answer.
6. What happened to the temperatures of each material after the light was off? Explain your answer.
7. What happened to the heat energy in the containers after they were taken from under the lamp?
8. What are some ways that you could change this experiment?
9. Identify the variable in this experiment and describe how the experiment would be modified by any change that you caused.

Extension:

1. Using a LAB PRO® (Vernier) or CBLs (Texas Instrument), place a temperature probe into a beaker of water (40 mL), and another temperature probe into a beaker of 40 mL sand, another in 40 mL of potting soil, and the last probe into 40 mL of gravel. Each probe should be at the same depth within each beaker.
2. Set up your system so that it records data for 10 minutes.
3. Place all four containers beneath a heat lamp for five minutes, then turn off the lamp. Make sure that the probes are still in the beakers.
4. Graph the data on a computer, either manually or allow LAB PRO® to create its own graph.
5. Compare the heating and cooling of each of the beakers.

Analysis:

1. Which of the materials showed the greatest change between heating and cooling? How can you explain this?
2. Which of the materials showed the least change in temperature between heating and cooling? How can you explain this?
3. What are some of the properties of water that allow it to have such a high heat capacity?
4. How does the high heat capacity of water influence climate?

Review science lab safety rules here.

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Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE Earth Systems Science core.

Updated October 24, 2008 by: Glen Westbroek