Does grass look green when it’s dark outside? Can you tell what color your sheets are when the lights are out? No! We need light in order to see colors. We call normal, everyday light from the sun, ceiling lights, lamps and flashlights “white light”. White light is made up of all the colors of the rainbow. If we shine white light through a special instrument called a PRISM, the prism will separate white light into all the different colors of the rainbow.
INTERACTIVE DEMONSTRATION: MAKING A RAINBOW
Demonstrate how the prism works by allowing the children to shine a flashlight into it and identify the different colors they see. Results may be more effective with the light off.
Q: What material acts like a prism in nature? Hint: The sun has to be shining at the same time this material is falling from the sky.
Q: How is water like a prism?
A: When sunlight shines through raindrops, white light is separated into the SPECTRUM.
Q: What happens when water acts like a prism?
A: We get a rainbow!
When light shines on an object, the object ABSORBS some of the light (like a towel absorbs water) and REFLECTS the rest (like a mirror). The color of that object is the color of light being reflected back into our eyes.
Imagine there is a red rose growing on a rosebush. If the rosebush is outside, what kind of light is shining on it? Sunlight! And what kind of light makes up sunlight? White light! And what colors make up white light? All of them! So when white light hits the rose, every single color in the white light is absorbed into the rose except for one; red light is reflected back into our eyes.
Q: When white light hits the LEAVES on the rose bush, what color is reflected back into our eyes?
((Point out children’s shirts and various brightly colored objects in the room, asking the same question; do not choose black or white!!))
Q: So if all the colors of light mixed together make up white light, what color do you think we see if ALL of them are reflected back?
Q: What color do you think we see if ALL the colors are absorbed and NONE of them are reflected back?
Hint: What’s the opposite of white?
Next, let’s talk about mixing colors together!
Image source: https://flic.kr/p/5YGWQH