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Probing Questions: Why is it cold in the winter and hot in the summer? Why is it the same temperature year- round at the equator? Is the sun directly overhead everyday of the year? Materials:
1. Paint the sphere black and let
dry completely.
2. Go outside of a sunny day and place the sphere on the ground. Hold the paper tube so that the end near the sphere is 20 cm from the sphere's surface. Adjust the tube so that a circular spot of sunlight falls on the sphere. Hold the tube in position for two minutes. Note the area and apparent brightness of the spot of light. See Figure 1.
3. After two minutes, insert the
thermometer in the center of the spot of light. Wait for the
thermometer to show its highest reading and record that temperature.
4. Remove the thermometer from the sphere and put it in the shade. Move the tube so that the beam of sunlight strikes the sphere at an angle of about 60 degrees. Be sure to keep the end of the tube 20 cm from the surface of the sphere. Hold the tube in position for two minutes. Note the area and apparent brightness of this spot of light. 5. After two minutes, insert the thermometer into the center of the area covered by the spot of light. Wait for the thermometer to show its highest reading and record that temperature. 6. Repeat this procedure for an angle of 45 and 30 degrees.
Results:
1. How does the area compare between the 90, 60, 45, and 30 degree angles? 2. How does the apparent brightness compare between the angles? Discussion Questions: 1.What conclusions can you draw from this experiment? Relate the results to the earth’s seasons. 2. Can you predict what the temperature would be for an angle of 15 degrees? 3. Explain when each of these examples would occur in our year? |
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