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Questions for Discussion: Primary Colors of Light and Pigments

What is a photon? Are all photons alike?
When white light goes into a blue filter, blue light comes out. How did the blue get into the light?
When red light passes through a green filter, no light gets through. What happens to it?
When red light is projected onto a white surface, red light is reflected. Blue light will similarly be reflected as blue. When both are projected onto a white surface, we see neither red nor blue. Is the red light still there? Is the blue light still there? What happened?
Explain why a sweater looks red. Start with sunlight or white light from a lamp striking the sweater.