Module 7

HOW HOT
IS THAT COLOR?

Student Guide

Jennifer Heidema, Jim Little, Rick Ramirez, Nancy Topoozian

You are at an outdoor sporting event with your best friends. Each of your three friends brought a soda with them but you forgot to bring yours. During intermission, your friends notice that you are thirsty; so they each offer you a sip of their soda. You know that all of the sodas have been sitting in the sun. Yet you must choose between three different colored soda cans. Which color can would you choose if you want to have the coolest drink possible? What is the relationship between the color of an object and the heat energy it absorbs from the direct sunlight?

1. To investigate the relationship between colors of objects and energy absorption
2. To understand the relationship between color, energy, heat and temperature.
3. To find a mathematical function that relates the rate of change of temperature with the color of an object exposed to sunlight.

1. With your group, plan an experiment that addresses the following:
   
   

   What Is the Relationship Between the Color of a Can and the Amount of Light Energy Absorbed?

   
   
   • Discuss with your group a working hypothesis that your experiment will test to answer the question raised.
   • Use the worksheet provided to record your group's prediction about the outcome of the experiment.
   
   
   
2. Set up the temperature probes
   • Connect the 3 temperature probes into ports CH1, CH2, and CH3 on the CBL.
   • Connect the black link cable from the base of the calculator to the base of the CBL.
     (Be sure these connections are secure.). If your set-up is in direct sunlight, you may want to shade the TI-83/CBL for protection.
   • Prepare the cans for the experiment. Note that the straws and clay can be used to guide and secure the temperature probes when inserted into the cans.
   
   
   
3. Set up the calculator program
   • Start the program titled PHYSICS on the TI-83 calculator.
   • Choose "1: set-up probes" then enter "3" for number of probes.
   • Choose "6: temperature probe" then enter "1" for channel number.
   • Repeat this step enter "2" for channel number.
   • Repeat again then enter "3" for channel number.
   • Select "2: collect data" on the main menu.
   • Select "2: time graph" on the data collection menu.
   • Select "1: non-live display" on the time graph menu.
   • Discuss with your group and choose the sample time and number of samples. (This may be something you change later to better observe the heat changes.)
   • Run your experiment, and record the results in the worksheet provided.
   • With your group discuss your experimental results and compare them with your predictions. Discuss alternative hypotheses, if your predictions were not supported by your experimental results.
   
   
   PROCEDURE: Part II
   • Test your alternative hypotheses by planning a new experiment using three soda cans of different colors.
   • Before you start your experiment, make predictions about the outcome. (Record on the worksheet provided.)
   
   
   
   • Discuss the results of your second experiment with your group and prepare an oral presentation for the class. Your presentation should take about 5 minutes and should address: 1) the hypothesis you tested, 2) your science/math results, and 3) your conclusions. To encourage creativity, your group presentation should be in the form of a skit, song, poem, cheer, or rap.
   
   
   
   
   

   APPLICATION QUESTIONS

   1. If you were to run this experiment over an extended period of time (a whole day or two days), do you think that you would find a linear relationship between temperature and time? Explain why or why not.
   2. Suppose your friends offered you sodas in blue, yellow, and white colored cans that had been sitting in sunlight for a half hour. Which color would you choose if you want the coolest drink? Which would you stay away from because it might be too warm to drink? Explain your reasoning.
   3. The sequence of colors in a rainbow represent the colors of sunlight in order of the energy of different colors of light (Blue light carries more energy than red light). Explain why a yellow can of cold soda left in the sun will not heat as rapidly as a blue can.
   4. You are designing a public park in a local desert community to include a playground, benches, and picnic tables. The theme of the park requires a variety of colors. What colors should you choose to ensure that the benches and tables can be "usable" on hot summer days. Explain your reasoning.
   5. List all of the variables that may affect heat absorption in the experiment your just performed.
   
   
   

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   Last modified 12 Aug 1997
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