Teaching Color Using Wavelength

By Laura Hospitál on Mar 17, 2017

Many thanks to my daughter, Hannah Hospitál, for this excellent idea.

As a science teacher at a school for the blind, I have often been asked how colors can be effectively described to students with visual impairment.  We often use descriptive words with colors such as "fiery red" or " deep purple".  These descriptions mean very little to students who have not experienced colors.  A more concrete science-based explanation of why there are various colors is the basis of this activity. It will be most appropriate for students who already understand the structure of a wave or in conjunction with instruction on waves. This hands-on activity provides students with a more concrete understanding of how color varies based on difference in wavelength.

Science concepts related to waves and wave structure may need to be reviewed in order for students to fully comprehend this activity.

Preparation:

• Give students each a card with a color
• Build relative wavelengths using Wikki Stix.
• Groups of 2-4 students working together or working with the itinerant TVI.
• As a guide, please see this activity for instructions on building the waves.using Wikki Stix: http://www.perkinselearning.org/accessible-science/features-waves-using-wikki-stix
• Prepare 3 waves with wavelengths from shorter to longer beforehand for students to use as a guide. The exact wavelenghts of this model is not important only that they vary from shorter to longer.

Related Vocabulary:

• electromagnetic spectrum
• color
• wave
• wavelength
• trough
• crest
• amplitude
• visible light

Procedure

Activity

• Pass out the 3 waves (with short, medium, and long) wavelengths to each group.
• Explain to the students that these waves represent wavelengths in the visible spectrum but that there would be actually much less difference between wavelengths in the visible spectrum
• Give students information on wavelength of colors in the visible spectrum (See below)
• Using the ranges given below  the students' task is to use the wavelength information given to determine which wave represents red, which represents.yellow, and which represents indigo.

Color Wavelength in nanometers

Red:  780 - 622 Orange: 622 - 597 Yellow:  597 - 577 Green:  577 - 492 Blue:  492 - 455 Violet:  455 - 390

Closure

• After each group has discussed and determined the three colors, discuss the scientific reason (differences in wavelength) that colors appear different.
• Review the related terms from above. See variations for students who are learning about the entire EM Spectrum.
• Teach the students the acronym ROY G. BV - the colors of the visible spectrum in order from greatest wavelength to smallest wavelength

Variations

• If this activity is completed with one student, make all of the waves and have the student place them in order from longest wavelength to shortest. Assist the student as necessary.
• Have students build their own waves to represent colors in the spectrum rather than building the waves for them.
• If students are learning about the EM spectrum, describe what  small portion of this spectrum visible light represents.

NGSS Standards:

Middle School - Waves and Electromagnetic Radiation

PS4.A: Wave Properties
A simple wave has a repeating pattern with a specific wavelength, frequency, and amplitude. (MS-PS4-1)