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Electromagnetic Waves Matchcard

The Electromagnetic Waves MatchCard introduces students to electromagnetic radiation as part of the Light & Energy Unit Study. Activities to compare length of frequency of waves are described.

science-matchcard

Electromagnetic Waves

Objective: Arrange the types of electromagnetic radiation according to frequency..

This MatchCard builds on Pitch and Intensity of Sound Waves MatchCard and the Light Spectrum MatchCard for students in 5th through 8th grade.

What is Electromagnetic Radiation

Electromagnetic radiation is emitted by the sun and stars. It is a form of energy consisting of waves of different sizes and frequencies. Visible light is one form of electromagnetic radiation. Other types also are transmitted to our planet from the sun; but many are filtered out through the atmosphere. Various forms of electromagnetic radiation are used in technology.

Types of Electromagnetic Waves

Students will become familiar with the following electromagnetic waves in order of decreasing frequency:

Gamma rays
X-rays
Ultraviolet waves
Light waves
Infra red waves
Microwaves
Radio waves

Length of Waves

It is easiest for students to grasp the wavelengths if you start with the largest (lowest frequency) first.

Remember this scale:

One meter = 1000 milimeters
1000 milimeters (mm) = 1 micron
1 micron = 1000 nanometers (nm)

Give the student the chart, and have them describe the wavelengths starting with the largest:

Radio Waves: 3 meters to 3 km
Microwaves: 3 microns to 1 meter
Infra Red: Waves 750 nm to 3 microns
Light Waves: 380 to 740 nm
Ultra violet waves: 10 to 380 nm
X-Rays: 0,03 to 10 nm
Gamma Rays: 0.03 to 0.003 nm

Frequency

Review the following concepts:

Frequency is the rate (or speed) of the waves, and is measured in Hertz. One hertz equals one cycle per second.
The larger the wavelength, the slower the frequency.
The smaller the wavelength, the faster the frequency.
Higher frequencies (smaller wavelengths) have more powerful waves.

Compare the frequencies of the following electromagnetic waves:

Gamma rays: 10¹⁹ Hz & Higher
X-rays: 10¹⁶ to 10¹⁹ Hz
Ultraviolet waves: 10¹⁴ to 10¹⁶ Hz
Light waves: 7.85 to 4.85 X 10¹⁴ Hz
Infra red waves: 1 x 10¹² to 4.3 X 10¹⁴Hz
Microwaves: 3 X 10⁸ to 3 x 10¹¹Hz
Radio waves: 3 X 10⁴ to 3 X 10⁸ Hz

This is a good time to review scientific notation. If the student has not learned scientific notation, this next exercise will be meaningless to him or her.

Make a Chart
Make a chart of the frequencies above.
Write out the frequency in Hertz longhand (writing out the zeros instead of using scientific notation.)
Consider: Why would a smaller, faster wave be more powerful? (Compare it to a large, slow bullet or a fast, small one.)

Made to Scale
Develop a scale showing the spectrum of electromagnetic radiation.
Let one milimeter equal 1000 hertz.
Note that the visible light is only one very small slice of the total spectrum.

More About the Waves

As an additional project, the student can make a chart, poster, or write a paper about the technological uses of the different forms of electromagnetic radiation.

Using the Electromagnetic Waves Matchcard

This is the fourteenth Matchcard of the Light and Energy Unit Study. You can download the Electromagnetic Waves Matchcard here.

The student arranges the electromagnetic waves in the order of greatest to smallest frequency.

The second page is the Instructor's Guide with the correct answers.

The third page has the Information Pieces. Student's cut them apart and place them in the correct place on their copy of the Matchcard (first page.)

For more information on how to use the Matchcards, see the MatchCard Science Instructor's Guide.

MatchCard Science

The activities and illustration above are from MatchCard Science, a homeschool science unit study. For the complete Light and Energy Unit Study follow this link. This unit study provides:

hands-on demonstrations
MatchCard reviews to master the material
suggestions for science projects to complete
instructions on a complete unit study curriculum

Currently this curriculum is under-going revision. We are providing free access to the unit study, with the desire that you will provide feedback as you are field testing the materials.

Science Notebook

If you are just using this single project, and are not in need of a full unit study, you might want your student to complete a science notebook entry for this project.

Return from the Translucent Objects Matchcard to the MatchCard Science Main Page.