Radiation Budget Activity:
What's the Frequency, Roy G. Biv?
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Radiation Budget Activity: |
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Grade Level: 5-8
| Earth and Space Science: |
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| Science as Inquiry: |
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| Physical Science: |
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Students will discover and verify the relationship between Wavelength and Frequency of the Electromagnetic Spectrum. The visible light from the sun is actually composed of the colors red, orange, yellow, green, blue, indigo, and violet, which can become distinguishable when sunlight passes through a prism. A good way to remember the order of the colors is to note that the first letters of the colors spell out the name ROY G. BIV.
Divide class into groups of 3 if possible.
Draw a vertical line about 20 cm from the beginning of the adding machine tape and label it "Start". Also make a point 100 cm from the starting point. Draw a vertical line and label it "End". Cut the tape off of the roll leaving about 20 cm space between "End" and where you cut.
Draw three evenly spaced horizontal lines along the tape from Start to End. Make the top line red, the middle line green and the bottom line violet to represent three different colors in the spectrum of light.
Divide the red line every 14 cm with dark marks in red pencil. The green line should be divided every 10 cm and the violet every 8 cm. The marks that you make on the three color lines will represent the different wavelengths of the different colors of light. (NOTE: The true wavelengths are actually measured in terms of Angstroms. An angstrom is 10-8 cm or 0.00000001 cm).
Use masking tape to fasten the marked adding machine tape to a pencil.
Cut a manila folder along its crease. Then cut a rectangle out of the center of one of the long sides. This rectangle should be about 10 cm high and 5 cm wide as shown below.
Set the manila folder cut out on the table supporting it with the four books. Feed the end of the adding machine tape through the narrow space between the manila folder and the two back books until "Start" appears in the middle of the opening in the manila folder.
The member prepared with the Data Table should sit in front of the tape and manila folder model.
Begin timing as one member of the group slowly pulls the tape along. Try to pull the tape at about the same speed for every trial!
Make a mark in the appropriate box on the data table every time a wavelength mark is seen. When "End" appears, stop timing and counting.
Each group should make a "trial run" before starting the procedure. Perform the activity an additional 3 times marking the time and count for each trial.
On the data table, determine and record the average number of wavelengths observed for each color and the average time (in seconds) from start to finish.
Determine and record the frequency for each colored light waves. Note: frequency is defined as the number of wavelengths passing a given point per second.
| Trial 1 | Trial 2 | Trial 3 | Average | Frequency | ||||
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Count
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Time
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Count
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Time
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Count
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Time
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Count
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| Red | ||||||||
| Blue | ||||||||
| Violet | ||||||||
Student worksheet
Name_____________________________________ Date_______________________________
Compare the wavelengths and frequencies
of the three waves. Write about any patterns you notice in their relationship.
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Which color has the shortest wavelength? ____________
Which color has the longest wavelength? _____________
Which color has the highest frequency? ____________
Which color has the lowest frequency? _____________
What is the relationship of the red wavelength to the green?
__________________________________________
Red to the violet?_________________________________
What is the relationship of the red frequency to the green?
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Red to the violet?_________________________________
From your answers to the questions above, name the relationship
