Why are there colors? Explain like I'm six.

April 23, 2015 4:45 AM

My six-year-old son asked me a question I'm stumped by (one of many). He asked "Why are there different colors?" I half-attempted an explanation about light wavelengths and light reflecting off surfaces and soon realized I was a) over his head and b) over my own head. How would you explain the concept of color--of what color really is--to a six-year-old? Obviously very simple language is needed here.
posted by zardoz to Science & Nature (30 answers total)

You were answering "How?" when the question was "Why?"

A good answer for a six year old: "To make the world glorious."
posted by megatherium at 4:52 AM on April 23, 2015 [15 favorites]

Best answer: I think I would start with a prism, to show him how white light contains all the other colors of light. The wikipedia article for prism has a neat little animated gif that shows how they work.

Once he grasps that, it's easier to explain how different objects absorb the colors you don't see, and reflect the colors you do see into your eyes.
posted by JDHarper at 4:55 AM on April 23, 2015 [7 favorites]

So people can tell things apart.
posted by pompomtom at 4:59 AM on April 23, 2015 [4 favorites]

It might be instructive, or maybe not, to mention that for some people who are color blind and some animals there aren't any colors.
posted by XMLicious at 5:06 AM on April 23, 2015 [1 favorite]

Magic School Bus Episode 33 (Makes A Rainbow).
posted by MonkeyToes at 5:08 AM on April 23, 2015 [1 favorite]

I would just say because the sun gives us colors and our eyes can see them.

I didn't understand the electromagnetic spectrum, etc until I was much older than six...
posted by umwhat at 5:19 AM on April 23, 2015 [2 favorites]

I came in to say what pompomtom said. We can see colors so we can tell the difference between objects and items that are similar in size and texture. For instance, we know that blueberries are delicious, but certain red berries are poisonous.
posted by royalsong at 5:25 AM on April 23, 2015

Best answer: Well, Jedediah (old-timey names are so hot right now), colors exist because we see colors. That sounds crazy, doesn't it? It kind of is! The one thing you have to know is that white light, like the kind that comes from the sun, that's really all the colors put together. Yep, the sun right in the sky above us has allll the colors in it.

How does white light have all the colors of light? Well, what color is it when you close your eyes? Black! That's because there's no light. Now, Jed, different things reflect light in different ways, don't they? Look at my white shirt, if I put my hand next to it, it gets lit up. Now look at this red book cover, when I put my hand next to it, my hand is a little red. The reason it's red, is because the thing the book is made of absorbs other bits of the light!

Now, all the things in nature, they reflect different bits of light because of what they're made of. Plants are green because the things they are made up of block out other bits of white light and only reflect the green bits back to us. But we only see the green bits because the people, and the animals that came before us, who were able to see the differences in the reflected light, were able to use that to their advantage.

Imagine you were looking for hamburger in a field of grass, you wouldn't want to eat the grass, would you? What if you couldn't see the difference between the light bouncing off the grass and the burger, what if it was all gray or just one color. It would be hard to find that burger! So the people in the past who couldn't find that burger, they didn't go on to have kids, and the people who could, they had lots of kids and those kids had kids and that's why color exists: Because it helped us find food.
posted by jedrek at 5:35 AM on April 23, 2015 [15 favorites]

Simple English Wikipedia might be a good resource to keep in mind for these kinds of things in the future.
posted by box at 5:46 AM on April 23, 2015 [1 favorite]

When I used to work in a science museum, when I talked about vision I would sometimes start off by explaining that when we see, what's happening is light from the sun or a lightbulb is bouncing off of things and going into our eyes. This is 100% nonintuitive, and kids often regarded me with extreme skepticism. So it's a handy derail/a good starting point.
posted by mskyle at 5:54 AM on April 23, 2015 [5 favorites]

Colours help differentiate things; in nature often times the most beautifully colourful things are poisonous eg. poison dart frogs. It's a warning and a way to classify things. Colours contain codes. Leaves are green because they contain chlorophyll, the element by which plants are fed by the sun. Different colours allow insects and other animals to determine what they can eat. Colour provides camouflage but it can also allow things to stand out so they can be found by others of their own kind.
posted by h00py at 6:10 AM on April 23, 2015

Not six year old level but for you, to help think about colors in general
Radiolab
posted by edgeways at 6:20 AM on April 23, 2015

Best answer: We can see colors so we can tell the difference between objects and items that are similar in size and texture. For instance, we know that blueberries are delicious, but certain red berries are poisonous.

This is a bit Intelligent Design though. I would maybe just tell him that there are NOT different colours; there is just light, and it bounces off different things on different "channels" and depending on what channel light bounces off, we see different colours.

(Caveat: My understanding of this process is about at your son's level, so that might well not be right.)
posted by DarlingBri at 6:34 AM on April 23, 2015 [1 favorite]

Best answer: My answer to *you*: We have evolved to perceive variances in light that tell us more about the world. Different animals have evolved to perceive light in different ways, as benefits them. Some animals see more infrared or more ultraviolet. Some people see fewer colors; we call them colorblind.

To *a kid*: That's a pretty big question. Tell me more. We can go to the library and get some books about color. And we can look at some ways people use color. Will that answer your question?
posted by theora55 at 6:45 AM on April 23, 2015 [4 favorites]

Best answer: "In your eye, you've got three different kinds of detectors, each one detects a different colour of light, there's one for red, one for yellow, and one for green light, so that's why we see those colours differently. All of the other colours we see are actually a mixture of those three colours"

Then do some experiments to prove it. Play around mixing different coloured lights together, looking at things through coloured acetate, looking really close to a CRT monitor to see the pixels, splitting light with a prism etc.
posted by Ned G at 7:25 AM on April 23, 2015 [1 favorite]

Also, mention that there are kinds of light that we can't see (infra-red and ultra-violet), because we don't have the right detectors in our eyes, but some other animals do have the right detectors. I think that could be really an interesting idea for a 6 year old, whilst expanding on the distinction betweeen the physical (light) and the phenomen (colour) and is probably a good way of hinting at the existance of the electromagnetic spectrum without it being way over his head.
posted by Ned G at 7:31 AM on April 23, 2015 [2 favorites]

Minute Physics: Why Is The Sun Yellow and The Sky Blue?
posted by rada at 8:02 AM on April 23, 2015

Oh, JDHarper, is so spot on! Get that kid a prism to play with. See if you can make rainbows with the the garden hose. Introduce ROY G. BIV.
posted by BlueHorse at 8:08 AM on April 23, 2015

A color is when you only see part of the light. White is the exception, not the color: it's when all the colors are there at once.
posted by Rich Smorgasbord at 8:18 AM on April 23, 2015

Best answer: If you want to get downright philosophically honest--yes we perceive color to aid in identification of things to eat, avoid, etc. on evolutionary timescales--you can tell your kid that we have no idea why we sense "color" in the way we do. We don't know what's behind the subjective experience of color, the particular qualia that lends itself to people being able to disagree on the nuance of how a color appears.

Also, "we don't know, but a lot of people are trying to learn about it!" is a cool answer for a dad to be able to give a kid. I loved hearing those mysteries from my parents when I was really little (I'm pretty sure they caused the mind explosions that led me into the sciences).
posted by late afternoon dreaming hotel at 9:10 AM on April 23, 2015 [1 favorite]

Buy him a prism!
posted by miyabo at 9:28 AM on April 23, 2015

Color is as much in your eyes and brain as it is in the world.

Objects in the world reflect and refract light in different ways. Receptors in your eye can pick up and sense different light frequencies. Your brain comes to an understanding about it all. The visual cortex is one of the largest parts of the brain. A lot of your brain function is spent on making sense of what you see, including color.

Many animals have different eyes, and what they see is entirely different from what we see. Some animals see more colors and sharper colors than we do.
posted by Flood at 9:30 AM on April 23, 2015 [3 favorites]

Colors don't exist. Our eyes collect the energy of different wavelengths of light, and our brain translates them into colors.

Why? Because:
a) Differentiating between wavelengths conferred an evolutionary advantage in the distant past, and the trait has continued in our genetic line.
b) A wizard did it.
posted by blue_beetle at 11:05 AM on April 23, 2015 [3 favorites]

By all means, get him a prism. My father gave me one when I was six; I recall many happy hours spent sitting on the living room floor, intercepting beams of sunlight with it. Also show him what he can do, mixing paints and watercolors. Is yellow red + green or is green blue + yellow? Color wheels: a discussion for another day.
posted by Rash at 11:31 AM on April 23, 2015

Best answer: He asked "Why are there different colors?"

You are probably way overthinking this. Kids that age don't know how to ask really good questions. They ask "why?" 5 bajillion times because they are 6 and don't know how to ask sophisticated questions. A lot of kids that age will be thrilled if you hear their why as a request to "tell me cool things about this topic!"

Also, you don't have to have The Answer. You can say "Well, I honestly don't actually know the answer to that question. Let's look some things up!"

Once when my oldest asked me a question when he was 8, I told him "I don't actually know. Grandma would say x. Some folks would say y. Other folks would say z. Why don't you do some reading and decide for yourself what you think the best answer is." He got back to me 8 years later with a better answer than anything I had ever heard and I still rely on HIS answer as the one that makes the most sense.
posted by Michele in California at 1:46 PM on April 23, 2015 [1 favorite]

Response by poster: Wow, such great answers, I want to favorite ALL THE THINGS! I'll get a prism for starters, then take it from there. The boy is wicked smart (#gottabrag) and is saying already that he wants to be a scientist when he grows up. I'll be asking Mefites for more advice in the future!
posted by zardoz at 2:02 PM on April 23, 2015 [2 favorites]

Best answer: This competition is aimed at 11-year-olds, but the topic of last year's Flame Challenge was color, and the winning entries are online here.
posted by TrarNoir at 6:31 PM on April 23, 2015

Response by poster: TrarNoir -- that video on What is Color? is great, just what I was looking for! Though a lot of it will go over Boy's head, but that's fine.
posted by zardoz at 4:31 AM on April 24, 2015

for what it's worth, i think the reason that colours exist is likely because the main evolutionary advantage of seeing different colours is to identifies classes of objects.

if you just sit and take a look around, and start thinking what you're looking at, it seems that you're brain is trying to construct a meaningful representation of the sensory input using a whole pile of tools. first, there's spatial position. it's seems "obvious" that a neat way of interpreting spatial position is in a three-dimensional space that corresponds to the physical space we can navigate with touch.

but then you get extra information. in particular, light/dark and colour (hue) (saturation seems less interesting). there's no a-priori reason i know of why your brain couldn't just represent these as extra dimensions - things that feel like position but "mean something else". i guess that doesn't happen because it would be hella confusing, when matching up to touch. and perhaps also because light/dark is connected to position (it's used to infer depth, for example).

instead, your brain seems to have two new ways of perceiving things. light/dark, which is a largely continuous thing, and colour, which is "grouped".

light dark, as i've already said, is related to spatial processing. and since space is continuous, it seems reasonable that light/dark is continuous too. we don't have "names" for different kinds of grey because we don't have (need) names for different distances, roughly. it's a continuously varying spectrum - both physically and understood.

hue is also, physically, continuous (wavelength). yet our brain does something different. it's groups the values into categories: red, green, blue. to some extent, we know this is cultural, but i am not sure that's critical. what's important is what drives this process. and i think it's that the way we use this information is to identify things. we need to tell that those bright red mushrooms kill you, but the orange carrots don't. and we need to do that whatever the actual hue of the "red" mushroom. so, unlike light/dark, colour is used to put things in boxes. and so is perceived in a quantised way.

and that is why colour.

but i am having trouble explaining this to adults (if anyone ever reads this old thread). i have no idea how to convey that to your son.
posted by andrewcooke at 4:50 PM on February 29, 2016

This thirty-year-old alternative-newspaper column might be relevant to your interests.
posted by box at 5:45 PM on February 29, 2016