## Electromagnetic Spectrum

### Carol Houck

#### Description

Students investigate the properties of the electromagnetic spectrum.

#### Objectives

The student writes text, notes, outlines, comments, and observations that demonstrate comprehension of content and experiences from a variety of media.

The student knows that radiation, light, and heat are forms of energy used to cook food, treat diseases, and provide energy.

The student identifies forms of energy and explains that they can be measured and compared.

The student knows the various forms in which energy comes to Earth from the Sun (e.g., visible light, infrared, and microwave).

The student knows the properties of waves (e.g., frequency, wavelength, and amplitude); that each wave consists of a number of crests and troughs; and the effects of different media on waves.

The student recognizes that patterns exist within and across systems.

#### Materials

Per group:
White or manila paper (18” x 24”)
-Colored pencils or markers
-Resource materials

#### Preparations

1. A discussion of wavelength, frequency, and energy may be necessary prior to this activity.

2. A discussion of the various forms of electromagnetic radiation may be necessary prior to this activity.

#### Procedures

Knowledge/Skills:
-Students will understand the relationships between wavelength, frequency, and energy.
-Students will know various components of the electromagnetic spectrum.
-Students will relate various forms of electromagnetic radiation to wavelength, frequency, and energy.
-Students will use writing skills to demonstrate an understanding of the electromagnetic spectrum.

Part One: Wave Characteristics
1. Divide the class into groups of four. Have students do some preliminary research to help them accurately depict the electromagnetic spectrum and the relationships between the wavelength, frequency, and different forms of energy.
2. Have students create a diagram of a wave and label the wavelength, amplitude, crest, and trough.
3. Ask students to diagram a wave displaying high frequency and a wave with low frequency.
4. Have students diagram a wave displaying high energy and a wave with low energy.
5. Have students answer the following questions after completing Part One:
a. What is wavelength?
b. What is frequency?
c. What is the relationship between wavelength and frequency?
d. What is the relationship between wavelength and energy?
e. What is the relationship between frequency and energy?

Part Two: Visible Light
6. Ask students to arrange the colors of the rainbow in order of decreasing wavelength and make a colored diagram to illustrate their answers.
7. Ask students to arrange the colors of the rainbow in order of decreasing frequency and make a colored diagram to illustrate their answers .
8. Have students arrange the colors of the rainbow in order of decreasing energy.
9. Have students answer the following questions after completing Part Two:
a. Which color has the largest wavelength?
b. Which color has the greatest frequency?
c. Is the color with the largest wavelength also the color with the greatest frequency? Explain your answer.
d. Which color has the greatest energy?
e. What is the relationship between wavelength and frequency?
f. What is the relationship between wavelength and energy?
g. What is the relationship between frequency and energy?

Part Three: Components of the Electromagnetic Spectrum
10. Write the following energy types on the board: infrared, visible light, x-rays, radio waves, ultraviolet waves, and microwaves.
11. Have students list the energy forms in order of decreasing wavelength.
12. Have students list the energy forms in order of decreasing frequency.
13. Have students list the energy forms in order of decreasing energy.
14. Have students answer the following questions after completing Part Three:
a. What is the energy form with the greatest wavelength?
b. What is the energy form with the greatest frequency?
c. What is the energy form with the greatest energy?
d. What is the relationship between wavelength and frequency?
e. What is the relationship between wavelength and energy?
f. What is the relationship between frequency and energy?
15. Assess students' understanding of the electromagnetic spectrum.

Part Four: Follow-Up
16. Allow students time to research in order to answer the following questions:
a. What are examples of energy that travel in waves?
b. For what are these energy forms used?

#### Assessments

The following questions may be used to assess the understanding of this material.

1. Which of the following has the largest wavelength?
a. yellow light
b. blue light
c. green light
d. red light

(answer d: Red light has the largest wavelength.)

2. Which of the following has the lowest frequency?
a. yellow light
b. blue light
c. green light
d. red light

(answer b: Blue light has the lowest frequency.)

3. Which of the following has the highest energy?
a. yellow light
b. blue light
c. green light
d. red light

(answer b: Blue light has the highest energy.)

4. What is the relationship between energy and wavelength?
a. Energy is high when wavelength is high.
b. Energy is high when wavelength is low.
c. Energy is high when wavelength is high or low.
d. Energy is low when wavelength is low.

(answer c: Energy is high when the wavelength is low.)

5. Which of the following is true if the frequency of a wave is increased?
a. The energy will decrease.
b. The wavelength will decrease.
c. The amplitude will increase.
d. The period will decrease.

(answer b: There is an inverse relationship between wavelength and frequency.)

The diagram of the colors of the electromagnetic spectrum may be used for assessment. The following criteria may be used to assess the diagram and the group learning:.

A. Poster Criteria 45%
• Poster is 18” x 24”.
• A title is included.
• Labels are typed (no smaller than 36 font).
• Poster is neat.

B. Content 45%
• Information is accurate.
• Colors of the spectrum are in the correct order.
• Uses are listed.
• Displays evidence of scientific thought.
• An illustration tag is included that explains the relationship between wavelength, frequency, and form of energy.

C. Teamwork 10%
• All members cooperated.
• Each team member did his or her fair share.
• The project was completed on time.

Self-Reflection:
Imagine that you are a textbook publisher. You wish to create an illustration that accurately depicts an electromagnetic spectrum. Your illustration will be included in the newest edition of a middle school textbook which you hope to sell to the state of Florida. The present picture is outdated and lacks color. What would your picture look like and what items would you need to include?

#### Extensions

Enhancement:
Students can create a stage or concert scene and use various colored lights to “set moods” or highlight action.

Cutting edge technology has developed “light circuitry” instead of using metals or chemicals. Using the Internet, students investigate the latest in computer circuitry.

NASA space stations use “light pipes” to focus solar energy on various parts of the station. How does a light pipe work? Students can do additional research to find out how a plant transforms sunlight energy into matter. When is matter changed to energy?