Earth Systems
Standard VI, Objective 1
Title: How Hot?
Description/Objectives:
Design and carry out an experiment to compare the rates of heat absorption and of heat release of both soil and water.
Observe how these differing rates of heat absorption and release affect the air above the soil and above the water
Time required: One 50 minute class period
Student Background: The sun’s energy that is absorbed by Earth is spread throughout the atmosphere in three ways: conduction, convection and radiation.
Conduction is the direct transfer of heat energy from one substance to another. As air above the earth’s surface comes in contact with the warm ground, the air is warmed. Soil, water and air are poor heat conductors. Convection is the transfer of heat in a fluid. Air is a fluid. When air near the earth’s surface is heated, it becomes less dense and rises. Cooler, more dense air from above sinks. Radiation is the transfer of heat energy in the form of waves. When the sun’s energy moves by radiation, it does not need the presence of a solid, liquid, or gas.
Note to the teacher: Students might want to and should be encouraged to place their thermometers in different places.
Materials: ring stand, soil, metric ruler, boxes – they can be clear, plastic or a shoe box, thermometers – 4, overhead light with reflector or sun, water, tape, colored pencils, graph paper, student sheet (printed below)
Procedure:
1. This experiment can be done as an inquiry activity or with more teacher direction. The student sheet is set up as an inquiry, the procedures listed below can be copied into the procedures if you wish.
Directions:
1. Set up two boxes, one with soil and the other with water. The soil and water should be 5 cm’s deep.
2. Place two thermometer bulbs 3 cm’s deep. Place the other two close the first two, but the bulb should be 1 cm above the soil line. Use the tape to secure the thermometers and to label the thermometers 1, 2, 3, and 4.
3. Write a hypothesis.
4. With the light on, take the temperature of each thermometer every minute for 25 minutes. Write your data down.
5. With the light off, take the temperature of each thermometer every minute for 10 minutes.
6. Use your colored pencils and the graph paper to graph your data.
7. Write down your conclusion.
Scoring Guide
1. Students design experiment and record procedures……………..20 pts.
2. Students conduct experiments and record data…………………..20 pts.
3. Students graph results…………………………………………………5 pts
3. Students correctly answer questions…………………………………5 pts
4. Student writes thoughtful conclusion…………………………………5 pts
Answers to Questions:
1. Soil should heat up more quickly
2. The air above the soil should heat up more quickly. Why? Water absorbs heat slowly and releases it slowly. Soil heats quickly and releases heat quickly.
3. Soil should lose heat more rapidly. Why? Soil has less heat capacity than water; it does not store heat as well.
4. Answers will vary. Explanation should be logical.
5. A clear lid should increase temperatures.
Student page Name______
Title: How Hot?
Purpose: You can burn your feet at the beach and cool them in the water. Why do the water and sand feel so different? Does soil or water absorb radiation faster? How does the temperature of air above each surface change? You will design an experiment to find the answers to these questions.
Hypothesis:
Materials: ring stand, soil, metric ruler, boxes, thermometers (4), overhead light with reflector or sun, water, tape, colored pencils, graph paper
Procedure:
Write the steps down that you will take:
1.
2.
3.
4.
5.
6.
Data:
Graph (on graph paper)
Questions:
1. When the light was on, which heated up faster, the soil or water?
2. When the light was on, which heated up faster, the air above the water or the air above the soil? Why?
3. When the light was off, infer from your graph which lost heat faster, the water or the soil. Why?
- Was your hypothesis supported by your data? Explain
5. Predict how your data would be different if you placed a clear lid on the boxes.
Conclusion: