Light and color
Mix red, green and blue spotlights, then light an apple with different lamps to see why objects have colors.
Standards: 1-PS4-34-PS4-2
1Wonder
Sunlight looks white, yet after a rain shower it spreads into a rainbow. A strawberry looks red in daylight but almost black under a blue party light. Where do colors really come from?
2Explore
This activity needs a bigger screen
Turn your phone sideways, or open this lesson on a tablet or computer. The explanation and quiz below work here.
- Turn off the blue spotlight. What color do red and green light make together?
- Turn all three on. What color is the middle where they all overlap?
- Drag the spotlights apart and back together. Which other new colors can you make?
- Switch to Colored objects. Light the apple with a green lamp. Why does it look black?
- Which object looks the same color under every lamp?
3Explain
White light is a mix
A glass prism bends each color of light by a different amount, so white light spreads out into a rainbow: red, orange, yellow, green, blue and violet. White light is all these colors mixed together.
White light is a mix of all colors. Colored lights add up: red + green + blue = white. An object’s color is the light it reflects; it absorbs the rest. With no light of its color to reflect, it looks dark.
4Practice
What is white light made of?
5Recap
- White light is a mix of all the colors of the rainbow.
- Colored lights add: red + green = yellow; red + green + blue = white.
- Objects reflect their own color and absorb the others.
- Under light without its color, an object looks dark.