Virtual Lab: PhET Color Vision Simulation Lesson Plan

Submitted by: Sam Steele, South Habersham Middle School

Grade Levels: 3-5, 6-8, 9-12

In this lesson plan, students investigate how colors are seen by the eye through additive and subtractive processes. Then they connect their discoveries to real word situations that use these processes.

Students will:

  1. Investigate color perception, color addition, and color subtraction
  2. Discover how monochromatic light passes through colored filters
  3. Explore how red, green, and blue light mix to make the colors of the rainbow
  4. Connect discoverie about color vision to real world situations

Materials:

  • Computers or other devices with Internet access
  • Interactive whiteboard

Preparation:

This lesson features an interactive simulation titled Color Vision, developed by our award-winning partner PhET through the University of Colorado Boulder.  In this simulation students first investigate color perception, color addition, and color subtraction. Then they explore color addition with red, green, and blue light.

Watch the Color Vision video primer for an introduction to the Color Vision simulation’s features and uses. Then review the Color Vision Simulation Overview for a summary of the of sim controls, model simplifications, and prompts to challenge student thinking.

Preview and play with the Color Vision sim to plan how you will adapt it to your students’ needs. If students will be working in small groups, review tips on Setting Cooperative Gaming Expectations.

Depending on your classroom routines and available technology, you may want to consider these grouping options:

  • 1:1 with students and devices
  • Two to three students sharing one device and swapping ideas and the device back and forth
  • Station model where small groups rotate through using the devices.

Build background knowledge or reinforce topics with these BrainPOP movies:  Color, Light, Rainbows, and Electromagnetic Spectrum.

Lesson Procedure:

  1. Pre Lab:
    Ask students the following questions or prompts and discuss as a class before they engage with the sim and discuss their responses to each as a whole class.
    • Do lighting filters use additive or subtractive properties to bring light of a certain color to our eyes? Explain.
    • Do different color lights use additive or subtractive properties to bring light of a certain color to our eyes? Explain.
    • What are the primary colors of light?
    • Give an example of additive color from a place you see colors.
    • Give an example of subtractive color from a place you see colors.
  2. Lab:
    Have students open the Color Vision sim. Instruct them to click the single bulb and make sure they’ve set the filter color to white. Have them play with the controls associated with this part of the sim for 2-3 minutes to gain familiarity with how things work. Here are some things they should understand after exploring:
    • The thought bubble shows the color the woman sees.
    • The bulb color changes the bulb when using the light option on the right (yellow bulb)
    • The face and brain pictures toggle between surface and how the brain gets signals from our eyes.
    • The flashlight pictures toggle from single bulb to RGB combination of lights.
  3. Now have students investigate how our eyes see color when using lighting filters. Have them click the reset button on the bottom right corner. Using the colored (yellow) bulb, switch the beam representation to photon particle mode. Then ask:
    • What color light is coming from the flashlight?
    • What color does the person see?
  4. Have students try adding a green colored filter to the yellow bulb color. Have them describe what happens. Make sure they switch the beam to light particles to find out what gets through the filter, if anything.
  5. Now have students try each of these combinations, and note their observations for each. They can make this table in their notebooks: PhET_Color_Vision_Virtual_Lab_Table
  6. Ask students why we call the use of filters and dyes subtractive coloring. Have a class discussion.
  7. Now have students switch to the white light bulb. Ask the following:  
    • What colors do you see coming from the flashlight?
    • Do the filters affect the white light differently than they affect the yellow light? If so, what difference do you observe?
  8. Next, instruct students to click the RGB Bulbs icon at the bottom of the screen. Ask the following questions:
    • What are the primary colors of light?
    • What color does the person see when all of the sliders are all the way up?
    Now have them leave the red and green sliders up and turn off the blue and ask what color they see now. Then have them turn the green and blue back to max power and ask what colors they see. Finally, have them turn off the red flashlight and turn the green to max power. Now what color do they see?
  9. Explain to students that the colors they just made are complimentary colors to the primary ones, meaning they are  blends.
    Now challenge them to try to make the following colors based on sliding the power levels of each color to the correct position. Record your results in the table below. You can use percentages or fractions to estimate the power level.
    When they finish, ask them why we call coloring from light emitted by the flashlights additive color.
    PhET_Color_Vision_Virtual_Lab_Table_2
  10. Post Lab:
    Now ask students the following questions based on what they discovered:     
    • Do lighting filters use additive or subtractive properties to bring light of a certain color to our eyes? Explain.
    • Do different color lights (RBG) use additive or subtractive properties to bring light of a certain color to our eyes? Explain using evidence from your lab
    • What are the primary colors of light?
    • Give an example of additive color from a place you see colors.
    • Give an example of subtractive color from a place you see colors.

Related:

    Filed as:  3-5, 6-8, 9-12, Color Vision