Thursday, March 28, 2013

Cosmic Connections

There is a funny thing about the area of a sphere. If you look at the moon, you see a certain cross-sectional area. But the actual area of the moon is exactly four times what you are looking at. It's a funny thing, that factor of four.

If you know the area of a sphere, the volume is "trivial", as the mathematicians like to say. From the formula for the volume of a cone, 1/3(base)x(height), you get the volume of the sphere. The surface of the sphere is simply the "base" of a generalized "cone". Archimedes famously determined the volume of a sphere by a very ingenious and very different argument involving a cone inscribed in a cylinder. I don't know if he knew about the ratio of 4:1, but that's another pathway to the volume formula.

Of course it works both ways: if you know the volume of a sphere, as Archimedes did, you can back it up to get the formula for area. Again, I don't know if that's what Archimedes did. It would be nice to find out.

But without solving first for volume, is there an obvious way you can derive that special 4:1 ratio? It turns out you can indeed argue it from geometry without too much difficulty. It starts off looking a lot like Archimedes' argument: first, you incribe a sphere in a cylinder. And then you take a disc-shaped slice perpendicular to the axis of the cylinder. This is just like Archimedes so far. But then, to calculate volume,  Archimedes inscribes a double-cone inside the cylinder, and it gets pretty intricate. For the surface area, you don't need the cone. You just compare the areas of the cyldrical section and the spherical section, and it's easy to see they are equal. From this, you immediately get the surface of the sphere.

For a long time, I've had the idea that this ratio had some kind of cosmic connection with physics. I don't remember where I got this idea, but think it might have been a pure accident. See, there's a funny thing about the apparent size of the sun. The apparent diameter of the sun, as viewed from the earth, is pretty close to one hundredth of a radian. That means if you hold your hand out 50 centimeters in front of your eye, and stick out your pinkie finger, the sun will span about half a centimeter as measured across your fingernail. One percent.

You have to be careful not to compare apples to oranges, or in this case radii to diameters. Your arm is a radius and the sun is a diameter, so you the true ratio is of course 1:200. Since area goes as the square of the linear dimension, that means the sun occupies one part in forty thousand as compared to...the area of the sky? No, because we don't yet know the area of the dome. We're really comparing flat circles, which would be the equivalent flat area of the sky. The beauty of the 4:1 business is that we can immediately see that the area of the dome is exactly twice the area of the corresponding disk; so it follows that the ratio of the sun's area to the total area of the sky is 1:80,000 which is a pretty cool result.

Here's where it gets cosmically weird. The dome we see is exactly one half of the actual "sky", because there is just as much sky on the other half of the world. So the area of the sun to the total sky becomes 1:160,000 or exactly half of the visible ratio.

The funny thing is that number 160,000 happens to be a perfect fourth power: specifically, it is 20^4. You know it's not that unusual to hit a perfect square. Perfect cubes are not that common. Perfect fourth powers are pretty rare...obviously, there are only 19 of them smaller than 160,000. But so what?

Fourth powers are not only a bit rare among natural numbers, but even more rare in physical laws. Most laws of physics have squares in them, but there is a law of thermodyanamics that says a black body radiates heat according to the fourth power of absolute temperature. So if you make something twice as hot, it radiates not twice as much heat, not four times as much heat (square law), but sixteen times as much.

Now we're going to put it all together. The temperature of the earth is around 300 degrees Kelvin (absolute scale). The earth is therefore radiating heat into the vastness of space according to the Laws of Thermodynamics. Unless that heat is being replaced by an equivalent source, the earth must therefore be cooling down. The fact that we aren't cooling down tells us how much heat we are aborbing from outer space.

If outer space consisted of a gigantic dark sphere at a temperature of 300 degrees Kelvin, we would obviously be in thermal equilibrium. We would be radiating heat out to the giant sphere, and it would be radiating heat back to us. Both bodies would be radiating heat at the same rate. But in fact there is no giant sphere out there, just the endless vacuum. So we are getting nothing back.

Except for this tiny patch of the sky occupied by the sun. Since it is only one part in 160,000 of the total sky, and it is obviously doing the whole job that our hypothetical giant sphere was otherwise doing, it must be giving off power at a rate 160,000 times as great as the black body of 300 degrees. But in that case, we know how hot the sun is! Knowing that a black body radiates heat according to the fourth power of absolute temperature, we take the fourth root of 160,000 and find that the sun is exactly 20 times as hot as the earth, or pretty close to 6000 degrees Kelvin.

And that's damn close to the actual temperature of the sun.

Monday, March 11, 2013

Dimmer Circuit Puzzle

Have you ever had your kitchen dimmer switch turned down really low, and then the refrigerator cuts in and the lights go right out? The funny thing is that when the compressor turns off, the lights don't even come back on again. You've got to turn the dimmer up quite a bit to bring them back.

It works best in older houses where the fridge plug is on the same circuit as the overhead light, but you can often see it quite clearly even when they are on different circuits. I was at a friend's house the other day and I was showing them how this works, when something very unexpected happened. The fridge cut in and the lights got brighter. I thought we were imagining it but we watched for several cycles, and it kept happening. Then we tried turning on the microwave, and the lights got dimmer. But the fridge definitely made it get brighter.

I think I figured out what is going on, and the answer is kind of interesting. It's really a two-part question: part 1 is just why is a dimmer switch turned down low so very sensitive to small changes in line voltage; and part 2, why the anomalous result of the lights getting brighter?

I'm including a simplified schematic of the dimmer circuit for your edification: I'll give you my answer when we return.

(I found the schematic on this very impressive website.)

Thursday, March 7, 2013

Curriculum? What curriculum?

This is the final installment of my story of how I got fired from UCN back in 2006. My inexplicable refusal to follow the curriculum was the reason they gave for letting me go. But there's an ironic twist to that story....


That just about covers it except for one small item you might still be wondering about: the mysterious eighth paragraph. I have said already that in seven paragraphs out of eight I am accused of not following the curriculum. What about the eighth paragraph?

In this paragraph Henning describes my very first day of work, going over how I was shown filing cabinets full of material including worksheets, old tests, blueprints, etc. It happens to be the longest paragraph of the entire letter, and yet it doesn’t include any particular complaints against me.  So what is it doing in my letter of rejection?

The eighth paragraph purports to show that the College provided me with all the resources I needed to do my job: which is to say, they basically shoved me in front of a filing cabinet and said “Knock yourself out”. But oddly enough, in the long itenerary of resource materials listed by Henning, there is one item conspicuously absent: a copy of the apprenticeship curriculum! I became aware of this deficiency in November and immediately wrote my supervisor requesting that one be provided. Selwin ignored my request; or to be more precise, he first said that he would get it for me, later said there were complications (what happened is that Murray actually freaked out when he heard I was asking after the curriculum!),  and finally never followed up at all, which was typical behavior on his part. (Everyone who has ever worked with Selwin knows this is true.) The ultimate irony is that the very curriculum which I am accused of not following is a curriculum which the College wouldn’t give me. 

Monday, March 4, 2013

In Which I Call A Spade a Spade

For the last two weeks I have been re-telling the story about how I was fired as an instructor from the University College of the North. Today's installment is about an incident that did me untold damage in terms of my reputation, but which ultimately was not even mentioned in the letter which listed the reasons for my dismissal. The reason it didn't make the list is because the College knew it was a malicious slander from the get-go. The report by independent consultant Joyce Oddidison was subsequently destroyed, but the damage had already been done. Here then is the continuing story...


I suppose in the end it’s all very well for me to write a self-serving letter which makes me out to be the hero and everyone else to be the villains. But what does it really prove? Ultimately, you can say that I was probably fired because I was a bad teacher. The point is, that’s not what the College chose to say. They said that I wasn’t following the curriculum, and that I was repeatedly warned and given a chance to comply. That is a lie and a slander which Katherine McNaughton, Selwin Peter, and Murray Oman conspired to establish and maintain, and to which Denise Henning has signed her name. The truth of my claim can be clearly seen in the patently absurd examples which the College has cited as so-called evidence of my inappropriate teaching.

I wasn’t fired because of the smokestack or the water heater or even the slope question. It’s almost as though I was fired simply because something about me inspires a profound, inexpressible loathing among certain people; that in an institution which claims to value “diversity” as its highest ideal, I was just too different. And the best excuse they can come up with is the smokestack issue. In fact, over the course of the year there was a never-ending stream of malicious gossip about me, including at least two claims of sexual harrassment! All of these were investigated by management in a desparate attempt to throw dirt on my reputation and  none of them were found to have any validity. That’s why they’re not brought up in my letter of rejection. But at least one of these incidents deserves further mention, because everyone on staff at the College heard about it at the time and I would like to set the record straight.

Elvis Balfour was a student of mine who lost his temper in class one day for no sensible reason, jumped over the desks and began shaking me by the throat. I remained calm and put up no physical resistance. When it was over, I told him to stop acting like a baby and get back in his seat. Subsequently through no action on my part, by the end of the day Elvis had been expelled from the course by Murray Oman.  

What happened next is confusing: Murray has been an instructor for many years and has routinely expelled students in the past without controversy (including the very same Elvis Balfour on a previous occasion). For unknown reasons, this time the College chose to disregard its own zero-tolerance policy on violence, refused to ratify the expulsion and instead relocated Elvis to The Pas where he was allowed to finish the course. An outside consultant by the name of Joyce Oddidison was hired by the College to investigate the affair, and she ultimately produced a report that blamed me for provoking the incident.

Oddly, Ms. Henning chooses not to mention the Elvis Balfour incident in her letter. Why, when she is clearly trying to make the strongest possible case for my dismissal, does she not invoke this glaring example of  misconduct? The answer is simple: there never was any misconduct on my part and Henning knows it. The report by Oddidison is a pack of lies, which she was hired by Selwin Peter to produce in order to justify his own idiotic decision to keep Balfour in the course.

Most notably, the argument Oddidison uses to condemn my behavior is based on a shameless doctoring of my own written submission. In particular, she places my words, “Stop acting like a big baby...” ....BEFORE the violent outburst rather than after, turning it into a provocation. Perhaps she thought I was lying. If so, she should have said so, and introduced testimony from other witnesses to back up her conclusion. That’s not what she chose to do: instead, she falsely manipulated my own words to make me guilty by explicit admission!

The College was an active participant in this slander and they know it to be false. The proof is simple: if they believed their own report, they would have included its conclusion in the letter which gives the reasons for my dismissal. Instead, they say I was fired for measuring the height of a smokestack. What jackasses they are.