What happens to a red apple when only green light shines on it?
Look… a shiny red apple, happy in the light. A red apple throws red light back to your eyes — that's how you see its color. Now a green light is going to click on, all by itself. So tell me… when only the green light shines, will the apple stay red, or will it go dark?
After you watchWhat happens to a red apple when only green light shines on it?
The short answer
Under only green light, a red apple looks dark, almost black. The color you see is light bouncing off the apple, and a red apple can only bounce red light. Green light has no red in it, so the apple has nothing to throw back to your eyes and it looks dark.
Try this next
- What if you shine a blue light on the red apple instead of green? Guess first — does the apple light up, stay red, or go dark? Then picture whether blue light has any red in it for the apple to bounce.
- What happens to a green leaf under that same green lamp? Guess whether the leaf goes dark like the apple or glows — then think about whether green light has the leaf's color in it.
The whole story
How it works
A red apple makes its color by bouncing red light back to your eyes and soaking up the other colors. Green light is full of green and has no red inside it. So when only green light shines, there is no red for the apple to bounce, the apple soaks the green up, and it sends almost nothing back. With no light reaching your eyes, the apple looks dark.
What people get wrong
Little kids think the red lives inside the apple and can never change, so the apple must stay red in any light. But the apple's color is really made by the light. Take away the red light and the red has nowhere to come from, so the apple looks dark even though its skin never changed.
The catch
A green party light makes green things glow, but it hides the true color of red things and makes them go dark. White light, like sunlight, has every color inside, so everything shows its real color, but only because nothing is missing from the light.
Questions kids ask
Does the apple really change, or does it just look different?
The apple does not change at all. Its skin is exactly the same red. Only the light changed. With no red light to bounce, the apple cannot send red to your eyes, so it looks dark until red light comes back.
What brings the apple's red back?
Any light with red in it. Shine sunlight, a white bulb, or a red lamp on the apple and its red pops right back, because now there is red for the apple to bounce to your eyes again.
What would a green leaf do under that same green light?
It would glow green. A leaf bounces green, and green light is full of green, so the leaf has plenty to throw back. The same green lamp makes the leaf glow and the apple go dark, because each one can only bounce its own color.
Talk about it
- Guess first: if our whole room turned green, which of your toys would disappear?
- Where do you think an apple's red really lives — in the apple, or in the light?
- Have you ever seen colors look weird under party lights or store lights? Why might that happen?
For grown-ups
A surface's color comes from selective reflection: pigment in the apple skin absorbs most wavelengths and reflects mainly the long red ones. You only perceive a color when that wavelength is both present in the light and reflected by the surface. Under a narrow green source there are no red wavelengths to reflect, the green is absorbed, and the apple reflects almost nothing, so it reads as near-black. This is why perceived color depends on the light's spectrum.
Keep going
What else makes you wonder?
- If a red apple goes dark in green light, what would a green leaf do?
- What color do you think a yellow banana would be under a blue light?
- Where does all that soaked-up light go when the apple looks dark?