Monthly Archives: February 2010

Let's Talk About Science

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Nice description of science (physics in particular) from the JREF forums.

As it turns out, we know enough to make really incredibly detailed descriptions. So detailed, we can describe things that we can’t actually sense directly with our own senses. We can measure those things, and we can describe them, but we can’t see them. So how do we know they’re right?

The answer is, reality appears to be consistent. In other words, our universe appears to be a place where, although random things can happen, not just anything can happen. Only certain sorts of random things can. For example, if you get out of bed and walk to the store and buy some brewskis and come home and sit on the couch and drink one, you’re still you. You don’t turn into a penguin when you walk around the corner, and you don’t cease to exist when you sit down on the couch. And this implies some things about the nature of our universe- and those things add up to consistency. Rocks don’t just disappear, or appear out of nowhere. The planet beneath our feet is there all the time, and holds us to itself.

Lots and Lots

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Physics Buzz: How Much Snow did Washington DC REALLY Get?

Washington DC looks like a 10 x 10 mile square with a bite taken out of it. All together the city is 68.3 square miles. It’s not too hard to figure out the total volume of snow dumped on the city so far.

55.6″ depth of snow x 68.3 square miles roughly equals 8,820,000,000 cubic feet of snow, or 249,000,000 cubic meters. If you were to build a giant cube of snow that big it would be 2,066 feet, or 629 meters on each side. That’s almost two fifths of a mile or two thirds of a kilometer per side. That’s the volume of about 238 Empire State Buildings. That’s a lot of snow.

It's Easy When Someone Else Does It

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Starts With a Bang: A Brief History of Time… in the New World!

It was only about a week before people noticed that the Sun and Moon weren’t rising and setting at the times they were supposed to! Apparently, the clock was running at the wrong speed, and was running slow by somewhere around a minute per day. This brilliant clock, which was accurate to within two seconds a day in Holland, must have broken somehow during the journey.

So what were the colonists to do? There was no clockmaker (or clock repairman) in the new world, and this clock was handmade and very valuable. They had no choice; the clock needed to be shipped back to Europe for repair.

So they ship the clock back to Europe, and they go to take the clock into the clockmaker, and it does the exact thing that your car does when you take it to the mechanic because it’s making a noise. It starts behaving like it’s perfectly fine. The clockmaker winds up the clock, and it immediately starts working properly, and keeps time to within two seconds per day!

The needed to appreciate the gravity of the situation, of course.

A very nice story, up until the last sentence:

So go ahead and take your standardized time for granted, but remember that it wasn’t always as easy as it is today!

Easy for whom? The dragons currently live at several picoseconds per day instead of several seconds per day. Scientists doing research are always trying to be on the part of the map that says “Here be dragons.”

The Demon's in the Details

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Uncertain Principles: Entanglement Happens

(Oops. I accidentally hit publish instead of save yesterday, and didn’t add my comment. Hence the time travel on the post.)

There are several application people try and use entanglement to pull off some neat trick (e.g. clock synchronization) and the problems Chad points out are often glossed over. It’s almost like the famous Sidney Harris cartoon, “Then a miracle occurs,” when the step in the procedure is “we take our entangled particles and move them an arbitrary distance apart,” which ignores the little demons Chad describes, that compromise your ability to know the measurement basis after your system has been exposed to the real world. It’s not quite at the level of ignoring the second law of thermodynamics and proposing a perpetual motion machine, but it’s almost as naive to propose it for an arbitrary system, without working out the details.

I Wonder How it Ends?

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Kottke three-fer

Insanely deep fractal zoom

The final magnification is e.214. Want some perspective? a magnification of e.12 would increase the size of a particle to the same as the earths orbit! e.21 would make a particle look the same size as the milky way and e.42 would be equal to the universe. This zoom smashes all of them all away. If you were “actually” traveling into the fractal your speed would be faster than the speed of light.

(Spoiler alert … The butler did it, and the chick is really a guy, and they faked their deaths to pull off the con)

The Red Pen Brigade

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Cocktail Party Physics: a few choice words from the red pen brigade

Some more on the topic of targeting your communication, and the utility of editors.

The hardest thing about teaching anybody anything is finding the right level of communication, and the right way to express the concepts. It would seem logical that you don’t go all jargony on a rank beginner, anymore than you have to spend time explaining the basics to an expert. But you’d be surprised how hard it is to put that into practice. How much knowledge do you assume? And how clear an idea do you as an instructor or writer have of what each level of knowledge actually includes? One of the tricks of being a good teacher is to remember what it was like when you were just starting out. What didn’t you know then that you know now? And then you determine the correct order in which to teach it.

But that’s not all that you have to worry about, either. The next problem is expressing that knowledge clearly in a way that will allow the listener or reader to follow your argument and build on what they already know. When you’re teaching, you tend to do this in a number of ways, using various media. You drag in handouts, you assign textbook readings, you draw pictures, you write concepts and key vocabulary on the board, you use PowerPoint, videos, diagrams, whatever you can get your hands on to reinforce what you’re saying in your lecture. But in the end, it all boils down to words, and if you’re not using them effectively and clearly, your students or readers are sunk.