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Learning Track

Introduction to Light

• What is Light?
• Light as a wave
• Light as a particle

Properties of Light

• Speed of Light
• Polarization

Color

• What is color?
• Emitted light
• Reflected light
• Mixing colors

Optics

• What is optics?
• Reflection
• Refraction
• Mirrors
• Lenses

Mixing Colors

This is the part that gets really exciting. What happens when more than one color of light reaches our eyes from the same point? Actually, the brain can perceive only one color at each point. When both red light and green light reaches our eyes from an object, for example, it actually appears yellow! It is important to remember that no yellow light is being emitted or reflected from the object. Our brains just interpret it that way. Most of the colors that we perceive can be produced from mixing just red, green, and blue light in different combinations and brightness. All three colors mixed together produce white light!

And yet this seems to go counter to what we experience as kids mixing different paint colors together. Usually, when we mix all the colors together, we end up with a dark or grayish mess, definitely not white. Why the discrepency? First of all, mixing light is an additive process. Mixing pigments (like paint) is a subtractive process. Remember, first of all, that a red object simply absorbs all colors and reflects only red light. Paints also work like that. When you mix paints, therefore, it absorbs more and more color, until finally, it absorbs all color and you see it as black!

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