Science project

Light Absorption and Color Filters

A yellow color filter will let through only yellow and absorb all other colors. So when blue light is allowed through a blue filter onto a blue object, the object will still reflect blue and therefore appear blue. But when blue light from a blue filter hits a red object, the blue will be absorbed and no light will be reflected, giving the object an appearance of being black.


blue filter



  • Flashlight
  • Red, blue, and green construction paper
  • See-through colored cellophane paper
  • Camera filters in red, blue and green
  • Masking tape or a rubber band

Research Questions

  • Why did the papers look white, red, blue, and green (respectively) in white light?
  • How did the filters affect the white flashlight beam?
  • Why did the yellow and green papers seem to lose their color when red light was shined on them?


  1. Darken the room as much as possible.
  2. Turn on the flashlight and aim it at the white paper. Observe and record the color of the paper in the data table.
  3. Repeat step 2 with the red, blue, and green pieces of paper.
  4. Place the red filter in front of the beam of the flash light as shown using tape or a rubber band to secure the cellophane paper filter. Shine the filtered beam on the white, red, blue, and green papers and record the colors seen.
  5. Repeat using the blue filter and then the green filter. After each test, record the results.






Digging Deeper

Place a filter in front of the light source. Combine two colored filters. Now combine three colors. Experiment with many different combinations.

Disclaimer and Safety Precautions provides the Science Fair Project Ideas for informational purposes only. does not make any guarantee or representation regarding the Science Fair Project Ideas and is not responsible or liable for any loss or damage, directly or indirectly, caused by your use of such information. By accessing the Science Fair Project Ideas, you waive and renounce any claims against that arise thereof. In addition, your access to's website and Science Fair Project Ideas is covered by's Privacy Policy and site Terms of Use, which include limitations on's liability.

Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

Add to collection

Create new collection

Create new collection

New Collection


New Collection>

0 items