my life 2008

In grade school, I learned a lot of tricks of memorization. I could memorize a list of words -say a hundred- in about 5 minutes. I made my own connections, so the words didn’t have to be connected in any way. I memorizred the Gettysburg address, as well as poems, etc. Much of what I memorized is still with me, even today. But today I learn. It is important to me to /know/, not memorize. So I try to understand. I think I understand what you are saying.

Glad to see you had a little time to get back to it. I try to check your site every so often, but sometimes slip up, and don’t check for several days. I miss you more when I can’t ‘read your mind’, so to speak. I’m not sure I understand you better, but I certainly try to know what you are doing, and above all, how you are doing. Daddy

Thanks, Daddy. :)

I forget, sometimes, that I’m often just as cut off from everyone working in Colorado Springs as I was when I deployed and began this page so everyone who wished would know I was all right.

I’m learning to balance my time better. I’m presenting a paper at a conference on 12 Mar 08, and have been working on that off and on for a couple of months (and soon, I’ll write the first word of it). I keep my work at work fairly well; this is easier now that I’m more comfortable in the classroom and often know how to teach a lesson, although I incessantly tweak my approach. I grade faster, marking less. I’ve learned to be more productive at work by often pointedly not opening emails until I’ve finished teaching for the day (and I shut off the Outlook notifier which only distracts me when I’m working each time a new email hits my inbox). That leaves me with off-duty time to study French, which I’ve made some progress with, even though I’m not as faithful as I should be. On the weekends, I go to Denver and see friends, or even go to the mountains (this last weekend, a bunch of us went up to Salida, CO, just under Princeton Peak, and rented a cabin with a private hot spring). I even find time to read things for pleasure from time to time.

Shocking, I know.

I’ll try to remember to give you more opportunities to read my mind. :)

Love,

d

Diana,

There were things that I’d memorized to get through school - complex arithmetic, stuff like that - that I ended up needing to really understand later on. Once I started to think about them, I found that the memorized version in my head faded (or more accurately, was distorted) before the undestood version was complete. There was a period of a month or two where I couldn’t calculate AC power (which involves trigonometry) worth a darn.

Long story short, I find that having an application in mind really helps with understanding.

By the way - the reason the colors are different between the color wheel and the color star is that the color wheel (involving pigments) is subtractive: a pigment subtracts unwanted colors from light, reflecting only the desired one. The color star is additive; the light sources are already a single color which blend to make other colors.

No, I don’t really get it either. But that’s what the book said. (Actually It’s harder for me to understand because the so-called “mixing” of light doesn’t follow the rules of mixing other forms of electromagnetic radiation like radio waves, which I do understand. By those rules red + green = ultraviolet.)

Dave

Hm. The additive and subtractive thing sounds reasonable, but it still doesn’t help me.

I thought the difference had something to do with how one wavelength alters another, but that doesn’t make sense, either (would one wavelength have any effect on the next?). ‘Tis perhaps the way different combinations of wavelengths affect our cones….

I can do the memorization thing easily, but I’ve found it’s no good to me except for making a grade. After that, I pretty routinely flush the “memorized” information, which makes me wonder if there’s really a greater purpose to higher education* if I can’t remember what I “learned.”

* Other than “I probably won’t have to wait tables again,” I mean.

“Distorted” describes my feeble grasp of French quite well, come to think of it. :)

d

Diana,

Two electromagnetic waves in free space don’t affect each other at all. Only if they combine in a nonlinear system (a description of which is WAY beyond the scope of this discussion) is there a noticeable difference, and then they combine to create new frequencies that are the sum and difference of the two original ones. (That’s what I meant when I said red + green = ultraviolet.)

I’m sure the mixing is actually occurring in our eyes, so it’s a perception matter. When a human is involved, all bets are off. (grin)

My psych teacher in college told us the reason we had to “learn” so much useles stuff was because we didn’t know what we’d need in life until later, but that it would be much easier to re-learn once we got there. He was a bit of a flake but I have to admit he was right about that part.

Dave

Well, two beams of light that cross will interact, but so slightly (only through Pair Production, I think) that we can pretty much discount it.

HOW OUR EYES SEE COLOR: INSERT SUBTITLE HERE
We have Long, Medium, and Short wavelength cones in our eyes. This means that all colors we can see will be encodable as a trio of intensities, corresponding to how strongly each of these three cones are transducing light energy to neural signals*. But each cone responds to a range of wavelengths: this means that pure 570 nm light will stimulate the L cone and the M cone about equally, and the S cone not very much, but still a little. Using the response strength of the three cones, the brain triangulates a single wavelength. In pseudo-math:
if light(X nm) = cones(L, S, M) is a mapping, then light(570 nm) = cones(strong, strong, weak) = yellow.

*though note that the colors and brightness of your surroundings are incredibly important to color perception, so a white A4 piece of paper will look white whether you’re outside or in a room lit only by bluish lightbulbs.

But a pure wavelength is not the only way to get the brain to receive “cones(strong, strong, weak)"; ergo, a pure 570 nm light is not the only way to create the visual percept* “yellow". Suppose you instead have a pair of pure light sources that, in isolation, could be described thusly:
light(700 nm) = cones(strong, pretty strong, very weak) = red
light(530 nm) = cones(pretty strong, strong, very weak) = green
Here’s where the additive part comes in. If you shine both of your light sources at the same spot on the wall, making light(700 nm) + light(530 nm), then you’ll get this:
cones(strong + pretty strong, pretty strong + strong, very weak + very weak). And that is roughly equivalent to cones(strong, strong, weak) = light(570 nm) = yellow.

*"percept” is a piece of jargon that I learned in the fall when I took the class titled Perception, and is used because the term “color” is ambiguous in this context.

So light energy composed of pure 570 nm looks the same to our eyes as light energy composed of both 530 and 700 nm; these two different lights are then “metamers” of yellow, by definition. “White” has a number of metamers (as it is cones(strong, strong, strong)) which are, also by definition, called “complementary colors".
NOW YOU KNOW!

K
Things get REALLY interesting when you consider the possibility of certain women to inheriting different L cones on each of her two X chromosomes. If the L cones are different enough, then she could be tetrachromatic, so we would have to describe her color percepts with the pseudo-math light/cones mapping of light(X nm) = cones(L1, L2, M, S).

Hi, Kevin! :)

So, you just said…yes, it’s in the perception…? I tried, but most of that (particularly the helpful equasions) made my brain seize.

d