Electromagnetic Spectrum and
Visible Light
Version History:
January 2012 – Douglas Lee
“Light” is a general term that describes the full range of wavelengths of
light called the Electromagnetic Spectrum. Human eyes are only
sensitive to a very small portion of the Electromagnetic Spectrum and
this is called “visible light”. Visible light corresponds to wavelengths in
the range of 400nm to 700nm (violet to red). The human eye cannot
see outside this color range.
This lesson will introduce students to the visible light portion of the
Electromagnetic Spectrum. An introduction to the Electromagnetic
Spectrum is given, followed by the components that make up visible
light. Three experiments are conducted which will illustrate the concept
of visible light: (1) white light is separated out into its constituent
components, (2) additive and (3) subtractive methods of color
reproduction are demonstrated.
th
Targeted Grade Level:
5 Grade
Subject:
Science
Process-Oriented Objectives:
Students will observe what makes up the components of visible
light.
 Specify skills/information that will be
learned
Education Standards Addressed:
Resources:
 Multimedia / computer equipment,
construction materials and tools used in
the lesson, if applicable
Materials List:
 Clear glass or plastic prism
 Red, green and blue (RGB) gelatin filters
 Cyan, magenta and yellow (CMY) gelatin filters
 3 LED flashlights
Tools List:
 None
Equipment List:
 Backlit projection device (e.g. overhead projector)
 Document camera
Topic Addressed:
 Description of the lesson, including key definitions and points
What is “Light”?
“Light” is the region of the Electromagnetic Spectrum that is visible to the
human eye. The Electromagnetic Spectrum is made up of different
wavelengths of radiation which transport energy from one location to
another.
Visible Light is the radiation that we can see.
Definitions:
“Light” or “Visible Light”
“Electromagnetic Spectrum”
Wavelength – the distance between the peak or crest of a wave to the
next corresponding peak
Putting the wavelengths of the Electromagnetic Spectrum into perspective.
What makes up white light? White light is the combination of all the colors of the visible light spectrum. To
demonstrate this, passing a white light through a prism will separate out the constituent colors of white
light.
What do I want the students to discover?
Understand that radiation comes in many forms and that our eyes are only capable of seeing a small
portion of the Electromagnetic Spectrum. The Visible Light spectrum is only a subset of the overall
Electromagnetic Spectrum.
Introduction Activity and Discussion:
 Introduce the activity
Show the chart of the Electromagnetic Spectrum. Use a SMART Notebook lesson to
display the Electromagnetic Spectrum. Use a SMART Notebook lesson to allow
students to understand the characteristics of the Electromagnetic Spectrum (size and
source)
What kind of electromagnetic radiation has the shortest wavelength? The longest?
What kind of electromagnetic radiation could be used to "see" molecules? A cold virus? A fighter jet (nonstealth version)?
Why can't you use visible light to "see" molecules?
Some insects, like bees, can see light of shorter wavelengths than humans can see. What kind of
radiation do you think a bee sees?
What does white light (the visible spectrum) made of? Use a prism and an LED
flashlight to break down the components of white light into individual wavelengths
of the visible light spectrum.
Color reproduction using additive and subtractive techniques on
visible light.
 Use the RGB gels and an LED flashlight to add colors to create
white light.
 Use the CMY gels and an LED flashlight to subtract colors to
create black.
Activity:
 Describe the independent activity to reinforce this lesson
 How will students be encouraged to investigate on their own, at school or at home?
Typical Discussion Questions:
Expected Conclusions:
Assessment:
Application to Real-Life Situations:
Students’ Literature Connection:
Integrating Other Subjects:
References:
http://science-edu.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html
http://www.ted.photographer.org.uk
http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html