A Post of a Different Color

Greetings Science Squaddies! Man have we hit the motherload this week! This is the joyous thing about science, asking questions provides answers, but it also provides more questions. I've always had an interest in color. The fact that there are soooooo many colors in the universe amazes me. Just walking around and taking note of all of the different colors that we see from day to day can be an eye opening experience, excuse the pun. When I see all of the colors, I then begin to think about the fact that in order for things to be different colors, there has to be an inherent structural difference to account for these colors. Then I start to get freaked out and I have to stop. Sometimes, being me is an odd experience.

So, when I had a hard time coming up with this week's post, I thought it'd be simple and I'll just write about what makes things different colors. As it turns out, that isn't a simple answer. When is it ever, right? As usual, the little sliver of knowledge I have on the subject is but a splinter compared to the great tree of ignorance currently growing on my intellectual property. That being the case, I think that we should take this journey together, me and you, and turn this into a series of posts. Come on, it'll be fun! Honest it will. All righty then, here we go:

What determines an object's color? (Or, why is the world a many colored thing?)

Today we'll lay the ground work before we get into the nitty and the gritty, there being a fair amount of both. Before we talk about color, we have to talk about light, because without light, there's no color, hence the difficulty one has when trying to read when sealed in a closet.

The interesting thing about color is that color is a human perception of a characteristic of light, namely its wavelength. We see the large wavelength part of the visible spectrum (the range of wavelengths of electromagnetic radiation that we can see) as being red. If our eyes developed differently, we'd see that portion of the spectrum differently, and it wouldn't be red any more. It's all very odd when you think about it. The spectrum goes from red down to blue, with red having the largest wavelength, and lowest frequency, and blue having the smallest wavelength and the highest frequency.

The simple reason that things are different colors, is because the light (for our purposes, I'm going to replace the words "electromagnetic radiation" with "light" as I am uncomfortable with the thought that I'm being constantly irradiated) coming from said object, and into your eye, has a specific wavelength and frequency that then gets interpreted by your brain as being red or blue or periwinkle. Of course, that's not much of an answer, as it doesn't really get to why light coming off of an object would be different in the first place.

As it turns out, there are 15 causes of color, that can be grouped into 5 groups. These groups are:

• Vibrations and excitations
• Ligand field effect
• Molecular orbitals
• Energy bands
• Optics

As you can see, we have a lot of ground to cover, and this doesn't even get into how and why color affects us emotionally, color theory in art, the science or measuring and reproducing color, and on and on and on. Oh the places we'll go!

For now, I think this is a good place to stop. Always leave 'em wanting more, I say. Plus, my kid is home sick, so I need to tend to her, and she doesn't take kindly to being ignored when she's perfectly healthy, much less when she's stricken with baby malaise.

Next week: I'm So Excited, And I Am Having Difficulty Hiding It

Sources:
Wikipedia - Color
Web Exhibits - Causes of Color
The Franklin Institute Online - Light and Color
The Physics Hypertextbook - Color