Reflection makes colors
Background
Your favorite orange T-shirt is that color because of reflection of light. Your dad's Ferrari (or Ferarri wannabe) is red because of the same reason, and your mom's bright pink running socks with the purple spots on them (that you tried to throw away but unfortunately she found them before the garbage was taken out) are that color for the same reason.
That is all good, but how can you prove what makes color?
Well, a good place to start is to make sure you know the meaning of what we are dealing with here. Check out the definition for
reflection
in Good-Science-Fair-Projects.com's online science dictionary.
Right, now that you have that basis...
Let's do science...
The Experiment
Let us review what we know:
white light comes to us from the sun during the day (and a certain amount is reflected to us from the moon during the night)
white light is made of seven colors (the colors of the rainbow) – check out the experiments
Colors of the rainbow
and/or
Refraction of light - how to make a rainbow
if you have not done so already.
So white light must be responsible for giving objects their color because color is more visible during the day and there are colors in white light. But how it happens ... well let's find out ...
The Aim
To show that the seven colors of white light are responsible for the colors of objects.
Equipment Needed
Several colored objects, at least one of each object of the following colors: red, blue green, black and white.
See through cellophane paper, or camera filters: one of each of the colors – red, blue and green.
Method
Pick a good sunny spot to do the experiments.
Look at each of the objects as they are and then through each of the colored filters or cellophane paper.
Results
This is what you should see happening with no filters and with the various filters in front of the objects...
The black object: however you look at the black object, it will still appear black.
The white object : no filter - white, red filter – red, blue filter – blue, green filter – green.
The various colored objects will look different depending on the colored filters used. In the photo below you can see that with a blue filter, the blue bead still looks very blue, the red object looks black, and the black object still looks black. With the green and yellow beads, you can still see that they are green and yellow but they are heading towards looking black.
The Conclusion
Obviously, each object will appear the color it is, with no filter in front of it. This is because that color is reflected off that object, while the rest of the colors that make up white light are absorbed by the object. Check out the diagram below that show this.
Black absorbs all colors. So whatever filter is held in front of it, no colors are reflected and so it will still appear black. Check out the diagram below:
A white object reflects all colors and absorbs none. The filters will let through only the color they are and absorb all other colors. So whatever light reaches the white object, whether it is the full seven colors to make white light or only one color of white light because the rest have been absorbed by a filter, that is what color will be reflected and that is what color the white object will appear. Check out the diagram:
Remember, the filters, theoretically, will let through only the color they are 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, it will be absorbed and no light will be reflected, giving the object an appearance of being black.
This explanation can be applied to all the rest of the situations in the experiment.
The reason that the yellow and green beads still appeared slightly yellow and green respectively is that the blue filter that I used did not block out all the other colors entirely (it was not blue enough!). The explanation is that some green and some yellow light made it through the blue filter, but no, or very little red light made it through.
Get hold of a color spectrum and try and figure out why this would have happened.
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