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Easy Color Experiments: What Is Color? How Does Light Make Color? Why Do Some Lights Make Colors Look Funny?
Never Paint Your Bedroom While Using Green Lightbulbs
Never choose paint for your bedroom when all your lights have green lightbulbs. This is some of the best advice I have ever had. I know this advice sounds odd, but it is very sound advice. It is based on the physics of light and the science behind how we perceive color.
Light waves are all around us. Without these waves there would be no color. Our eyes are able to pick up these waves and decode them. We are going to do a quick activity and then we will discuss what happened and why it happened.
Let's get started...
Crazy Crayon Colors Science Snack
Materials For Crazy Colors Experiments
- Box of at least eight crayons, you need one crayon of each of these colors: brown, black, red, orange, yellow, blue, green, violet
- Some white paper to draw on
- A dark room, use one with as little outside light as possible
- A monochromatic lightbulb, we will use green
- A table lamp
- Remove the wrappers from the crayons so you can't read the color names.
- Put the green lightbulb in the table lamp.
- Take the lamp, crayons, and paper into the dark room.
- Turn on the lamp and then close out as much of the outside light as possible.
- Find a good surface for drawing. We are going to draw a picture. I want you to do your best to use the colors in these instructions.
- Draw a tree. Make the top part green and the bottom part brown.
- Draw a blue house with a purple roof. You may use black to add the windows and doors.
- Add a red chimney to the house.
- If you want to add any other details to your drawing, you may do so now.
- Once your picture is done, turn the green lamp off and go somewhere with regular lighting.
- Take a look at your picture.
Critical Thinking Questions
- What does your picture look like?
- Is it what you expected?
- Did you pick the colors correctly?
- How did you choose the colors?
- What did the colors look like under the green light?
- Why do you think that happened?
- What do you think would happen if we used a red light?
The Colors In White Light
What we think of as white light is actually made up of many different colors. When you mix all the colors together, you will see white. Prisms and diffraction grating are able to separation out the different colors of light. While white light is made up of a balance of red, orange, yellow, green, blue, indigo, and violet, other colors of light will be made up of different colors. The green lightbulb will mainly be made up of green light with a little yellow and blue and almost no red.
Take a look at the pictures to the right to see some examples of the different colors that make up light.
If you want to see some of the colors of the lights in your home, get out a CD and shine some light on it. The compact disk will break the light into its different colors.
Why Is Green Green?
The color that something appears is the color of the light that is bounced back to our eyes. A green object will reflect green light and absorb all of the other colors of light. The same is true for every other color that we see.
In the picture below we see
- White light is produced by a lightbulb
- All of the colors of light shine on the green spot
- All of the colors except green are absorbed by the green spot
- Green light is bounced off of the green spot
- The eye picks up the green light
- Information travels from the eye to the brain telling us what we are seeing
Why Did The Green Light Make The Crayons Look Funny?
So we now go back to your drawing. Do you have any guesses as to why the crayon colors looked funny in the green light? Let's look at some pictures.
The top one represents a white lightbulb. The full color spectrum is shining on a red spot and a green spot. The red spot reflects back the red light, it enters the eye, and the brain sees that the spot is red. The green spot reflects back the green light, the eye picks it up, and the brain sees a green spot.
The bottom picture represents a green lightbulb. A green spectrum is shining on a red spot and a green spot. The red spot has no red light to reflect back to the eye so the brain will see a grey-green spot. The green spot reflects back the green light, the eye picks up the green light, and the brain sees a green spot.
In the experiment you used crayons that were made up of all different kinds of colors. With regular light shining you are able to use the full spectrum of colors to perceive the actual color of each crayon. When you turned on the green light you no longer had a full spectrum of light. Your eyes only picked up light colors that were available from the green lightbulb. These colors were predominantly green. This made the crayons all become some shade of green or green-grey. The only crayon that was close to its original color was the green crayon.
Even More Ways To Play With Light And Color
- Lots of paint sample cards from a paint store. Make sure to have a large variety of colors.
- A container
- The green light from above
- A dark room with little natural light
- Cut up the paint samples into individual colors.
- Place the color chips into the container.
- Take your green light into the dark room.
- Block out as much natural light as possible.
- Turn on the green light.
- Try to pick out individual colors from the paint chips and see how you do. Pick out a blue chip. Tape it on the paper. Label it "blue". Do the same think with some other colors (yellow, grey, pink, brown, etc.)
- Once you have a good collection, turn on the lights and see how you did.
Additional Activities And Information On Light And Color
- Color Uncovered for iPad on the iTunes App Store
- How to make white light from glow sticks
- Why sodium street lights make things look orange - Naked Scientists Kitchen Science 2007
- How to Remember the Order of the Visible Color Spectrum. Meet Mr. Roy G. Biv.
- ColorFest: The Art and Science of Color | Exploratorium