Lab: Absorption and Radiation of Heat

Transcription

1 Lab: Absorption and Radiation of Heat Purpose: To Investigate Absorption and radiation of heat Materials: 2 test tubes black paper test tub rack two thermometers aluminum foil small pieces of tape Procedure: 1. Cover one test tube with foil. Cover the other test tube with black paper. Fill the two test tubes half full of water. 2. Insert a thermometer into each test tube and place tubes in the test tube rack. Allow the water temperature in both test tubes to reach the same temperature. 3. Place the test tube rack with the test tubes in bright light so that the light strikes each tube equally and at the same angle. Record the water temperature (in Celsius degrees) every 3 minutes for 18 minutes in the data table. Beginning water temperature after 5 minutes Test tube + Foil Test tube + Black Paper Test tube in Bright Light: (Check each tube every 3 minutes) Test tube + Foil Test Tube + Black Paper after 3 minutes after 6 minutes after 9 minutes after 12 minutes after 15 minutes after 18 minutes

2 Report Questions 1. In which tube did the temperature increase most rapidly? 2. In which tube did the temperature change the least? 3. What roll did the aluminum foil have in the temperature change? 4. What roll did the black paper have in the temperature change? 5. Construct a line graph of the data collected. Place time on the x axis and temperature on the y axis. Use different colored pencils to indicate the temperature of the two test tubes.

3 2. Have a second member of your group drop the tennis ball from the top of the meter stick (100 cm mark) in such a way that is does not touch the meter stick on the way down. 3. Have a third member of your group note the height of the first bounce. The bounce height should be called out to the fourth member of the group, who should record it in Table 1. Let the ball continue to bounce and continue observing it for as long as you can. (It may take several trials because the ball may tend to bounce away from the meter stick.) 4. Repeat steps 1, 2, and 3 with the ping pong ball, the sponge ball, and the air filled rubber ball.

4 5. On Graphs 1 to 4, plot the height of each bounce for each ball. Draw a curved line that best fits through the vicinity of the points. You will plot four graphs.

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13 Testing Newton s First Law of Motion If you have ever pedaled your bike from a resting position, you know that it is difficult to get started. But once you are moving, pedaling is much easier. The reason for this sometimes unwelcome fact of life is that, as Newton explained, a body at rest will remain at rest unless an unbalanced force acts upon it. The other half of the law says that a body in motion will remain in motion unless an unbalanced force acts upon it. The tendency of a body to remain in its state of motion is called inertia. In this activity, you will have several opportunities to experiment with other examples of inertia. Materials Several coins 250 ml beaker Water Sturdy sheet of cardboard, large enough to cove the top of the beaker Cardboard roll from a roll of toilet paper Small potato Procedure Part A 1. Bend your arm so that your hand is near the back of your head and your elbow is level with your ear. 2. Place a coin on the flat part of your forearm near your elbow. 3. Quickly jerk your elbow down and catch the coin in the palm of your hand. Repeat steps 1 through 3 several times, each time increasing the number of coins stacked on your arm. How many coins can you successfully catch? Relate this activity to Newton s first law of motion.

14 Part B 1. Fill a beaker about two thirds full with water. 2. Place a sturdy piece of cardboard on the mouth of the beaker. 3. Stand the cardboard core from a roll of toilet paper on the flat piece of cardboard so that it is directly above the beaker of water. Glue the roll into position. 4. Set a small potato on the open end of the toilet paper core. 5. Pull or hit the flat piece of cardboard with a sharp horizontal force. What happens? Relate your observations to Newton s first law of motion.

15 The Planets Planet Distance (AU) Surface Gravity Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto One activity, using a solar system lithograph set, is to show a scale distance of the planets. Set the scale for one meter to equal one Astronomical Unit (AU). Use a meter stick and place each planet lithograph on the ground. A long hallway or large field will be needed. Place the corner of the lithograph of the Sun at zero and set each planet at the proper scale distance (Mercury at 37cm, Venus at 72 cm etc.). Another activity can enhance the teaching of multiplication with decimals. Determine the weight of an object on Earth then calculate what its weight will be on a particular planet. Note: Lithograph sets can be printed from the NASA website or you can have them printed by Office Max from this page. _Solar_System_Lithograph_Set.html

16 Vibrations in Matter Skills: Hypothesize; Observe; Infer; Generalize; Predict Problem How do sound waves affect solid, liquid, and gas media? Goals In this investigation, you will use a tuning fork to observe the effects of the motion of sound through air, water, and solid media. Hypothesis Carefully read the investigation before stating your hypothesis. Materials tuning fork drinking glass water cork string large rubber stopper Procedure 1. Observe Work with a partner. Hit the prongs of a tuning fork sharply against your heel or a large rubber stopper. Hold the fork upright near, but not touching your ear. Note what you observe. Rotate the handle of the fork slowly while the fork is still sounding. Note what you observe. 2. Fill the drinking glass halfway with water. Strike the tuning fork, and lower it into the glass so that the prongs just touch the surface of the water. Note your observations. 3. Strike the fork and hold the bottom of its handle against the top of a desk or table. Note your observations.

17 4. Strike the fork and let one of its prongs touch the side of the empty drinking glass. Note your observations. 5. Tie a length of string to a cork and hold the string so that the cork hangs from it. Strike the tuning fork and allow one of its prongs to touch the cork. Note your observations. 6. Strike the tuning fork and hold the end of its handle against the bone behind your ear. Note your observations. 7. Strike the tuning fork and allow one of its prongs to graze your cheek. Note your observations. Observations 1. What did you observe when a. you held the tuning fork near your ear? b. you touched the tuning fork to the water? c. the tuning fork was held against a table top? d. the tuning fork touched an empty glass? e. the tuning fork touched the hanging cork? f. the tuning fork was held against the bone behind your ear? 2. What did you feel when the tuning fork grazed your cheek?

18 Analysis 1. Infer What is the medium, or carrier substance, through which the sound of the tuning fork travels to reach your ear? 2. Infer What caused the effect that you observed when you touched the water with the tuning fork? 3. Infer What caused the effect that you observed when you a. touched the glass with the tuning fork? b. touched the cork with the tuning fork? 4. Infer What caused the effect that you observed when you touched the bone behind your ear with the tuning fork? Why was the effect different from what you observed in step 1 of the procedure?

19 Conclusions 1. Generalize What happens to a medium that is carrying sound waves? What kind of motion is associated with sound? 2. Predict Imagine you are a NASA astronaut taking a space walk outside the orbiting space shuttle. As part of an experiment, you have a tuning fork in one hand and a vibration sensing device in the other that displays 0 when no vibrations are detected and 10 when strong vibrations are detected. You strike the tuning fork against the side of your helmet. What number do you think the device will display when you bring the tuning fork 5 cm away from it? Explain.

20 Wave Behavior Skills: Predict; Observe; Infer; Compare and contrast Background Information Sound and light travel by wave motion. There are two basic types of wave motion: longitudinal and transverse. In a transverse wave, the medium moves at a right angle to the direction of the wave s energy. Water molecules in the ocean, for example, move up and down as waves move toward the shore. In a longitudinal wave, the medium moves back and forth in line with the direction the wave is traveling. Problem How do different types of waves behave? Goals In this investigation, you will use a spring coil to investigate the nature and properties of transverse waves and longitudinal waves. Prediction Carefully read the investigation before stating your prediction. Materials Slinky or other spring coil Procedure 1. Work with a partner. Stretch the spring coil along a smooth floor to a length of 3 m. Each partner should hold one end of the spring. Be careful not to overstretch the spring. 2. To send a single wave pulse to your partner that is similar to a lightwave, quickly slide your end of the spring from side to side one time along the floor. Your hand should move at a right angle to the direction in which the spring is stretched. 3. Observe Observe the motion of the wave pulse. Watch what happens to the wave when it reaches your partner s end.

21 4. Send several wave pulses in a row by repeatedly sliding your end of the spring from side to side. Then try increasing the rate. Note what happens to the distance between waves. 5. Try varying how far you move the spring from side to side while keeping the rate you move your hand constant. Note what happens to the appearance of the wave. 6. To make a wave similar to a sound wave, keep the spring stretched to a length of 3 m, with each partner holding one end. 7. Send a single wave pulse to your partner by quickly sliding your end of the spring forward and then back. Your hand should move in the same line as the spring is stretched. 8. Observe the motion of the wave pulse. Watch what happens to the wave when it reaches your partner s hand. Observations 1. When you made a wave pulse in step 2, did you move the spring in the same direction or at a right angle to the direction the wave pulse traveled? 2. What happened to the wave in step 3 when it reached the opposite side? 3. What happened to the frequency of the wave in step 4 when you increased the rate at which you moved the spring from side to side? What happened to the wavelength? 4. What happened to the wave in step 5 when you moved the spring farther from side to side? 5. Did the speed of the wave in step 5 seem to change when you moved the spring farther from side to side?

22 6. What happened when you pushed the end of the spring forward and back in step 6? Did the spring coils move at right angles to the wave, or in the same direction? 7. For either type of wave, did any of the actual spring coils travel from one end to the other? Explain. Analysis 1. Infer What type of wave, transverse or longitudinal, did you produce in steps 2 through 5? Explain your answer. 2. Infer What type of wave did you produce in steps 6 and 7? Explain your answer. Conclusions 1. Compare and contrast How is the movement of transverse waves and longitudinal waves different? 2. Infer Based on your answer to Observation question 7, describe how the movement of water molecules in a water wave is limited. 3. Infer Based on your answer to Observation question 7, describe how the movement of molecules in air is limited when a sound wave passes through.