Katie Redden
Lesson 1: Wavelength and Frequency of the Electromagnetic Spectrum
Grade: 7
Time Needed: 48 Minutes
GLCE’s:
 P.EN.M.3 Waves and Energy-Waves have energy and transfer energy when they interact
with matter. Examples of waves include sound waves, seismic waves, waves on water,
and light waves.
Objectives:
 Students will discover and comprehend the relationship between wavelength and
frequency of the Electromagnetic spectrum.
Materials:
 Manila Folder (One for each group)
 Roll of Adding Machine Tape
 Poster about Electromagnetic Spectrum
 Scissors
 4 books per group (for activity)
 Red, Green, and Violet pencils (A set for each group)
 Meter stick/ruler
 Timer
 Masking Tape
 Pencil
 Science Folder
 Worksheet
 Data Table for the Times on the Lab
 NASA Electromagnetic Poster
Introduction:
 Introduce the electromagnetic spectrum to the students. Have the NASA Electromagnetic
spectrum poster up on the front board. Explain to the students that the electromagnetic
spectrum is the full range of frequencies, from radio waves to gamma waves, that
characterizes light. Talk about wavelengths: Explain the parts of a wave and how
wavelength is always measured from trough to trough or crest to crest. Draw this on the
board for students to better understand the concept of a wave, and that we are not
referring to the waves of the ocean. Wavelength is the distance between identical
locations on adjacent waves. Explain Frequency to the students, It is the number of
complete waves, or wavelengths, that pass a given point each second. Light travels at the
same speed but each color has a different wavelength and frequency. This is what causes
the different colors of light to separate and become visible when passed through a prism.
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Students will be grouped based on their social studies groups from the morning lessons
(This is based on the religion they are an ‘expert’ on) In these groups every student needs
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a large chunk of adding roll tape paper, a meter stick/ruler, timer (clock in the room is
fine), Pencils, masking tape, 4 books, scissors, a manila folder, and Red, Green, and
Violet pencils. Students will all need their science folder/notebook.
o The on task coordinator should make sure that everyone, including themselves,
are on task at all times throughout the experiment.
In the groups students need to choose someone to be the Recorder, the reader, the
materials manager/checker, time keeper, and an on-task coordinator. The materials
manager needs to collect all of the materials listed above for their group and return them
at the end.
The recorder will take the adding tape and draw a vertical line at the beginning of the
tape to mark the start line (label Start). From the starting point draw another vertical line
100 cm away from the start and mark this END. Cut the adding roll here with a bit of
space at the end.
The materials manager will take the colored pencils and draw three evenly spaced lines
horizontally from start to end. The top line is red, middle is green and bottom is violet.
These lines represent the three different colors of the spectrum of light.
The recorder will make a vertical mark with the red pencil every 14cm on the red line. A
vertical mark will be made with green pencil every 10 cm on the green line. Finally, a
vertical mark will be made with a violet pencil every 8 cm on the violet line. These will
represent the different wavelengths of those colors of light.
The materials manager will use the masking tape to tape the end of the adding tape to a
pencil and then wind the adding tape back up.
The reader should cut a manila folder in half. Then cut out a rectangle that is 10cm high
and 5cm wide. This should be cut on the long side of the folder.
The Reader will then set the manila folder with the cut side on the table and use the four
books (one front left, one back left, One front right and one back right) to get the folder to
stand up straight. The adding tape should be fed through the space between the folder and
the back book so that you can see the word start.
The recorder should have the data table ready and be sitting in front of the folder set up.
Time keeper will call start and begin timing as the reader pulls the tape slowly along.
Make sure to pull the tape at the same speed each time.
The recorder will tally in corresponding boxes on the data table every time they see a
colored mark. When the END appears is when the time keep stops the time.
The first time should be a trial run and then the procedure should be completed three
other times.
The Materials Manager will find the average for the number of wavelengths observed and
the average time (in seconds) from start to end.
As a group they should determine the frequency for each of the colored light waves and
record their findings.
After students have completed the experiment they will complete the worksheet provided
to them.
Closure:
 Students will clean up their area and make sure that everything is put back where it is
supposed to be. Every student should turn in their worksheet at the front of the class.
Assessment:
 Students will be assessed on their completion of the Lab worksheet.
Adapted by Katie Redden, Northern Michigan University
http://imagine.gsfc.nasa.gov/docs/teachers/lessons/roygbiv/roygbiv.html