Monthly Archives: October 2013

I Come to Bury Math, not to Praise it

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The Death of math

I have no problem with the viewpoint that math instruction needs to improve, and that covering a lot of ground but only superficially is a bad idea. Plus all the standardized testing idiocy.

But I disagree with the “math should be an elective after grade 8” proposal. The point is not, as is suggested, to churn out a bunch of math majors. Math is the language of science, and people need to be math and scientifically literate — that’s why they should be taught math and science. If you don’t teach math, not teaching science necessarily follows. And there is no way to teach some science any way but superficially without math.

One could easily replace the math examples in that section with English and Shakespeare (or fill in your favorite novels), and much of it would read pretty much the same, and I don’t think that’s a selling point of the argument. The point of teaching English and Shakespeare is not because we expect all of our students to become literature majors in college. They take English because they have to be able to communicate effectively, and they study Shakespeare because culture is important, too. If people understood that math is a language, I think it would blunt some of these arguments. You don’t hear people arguing that little Timmy/Sally “isn’t wired for English” as an excuse for trying to get it out of the curriculum. Understanding math and science adds value to how one gives context to information and how one interacts with the world. It’s a necessary part of education.

Known Knowns, Known Unknowns, etc.

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Physics: What We Do and Don’t Know

Cosmology and elementary particle physics span a range from the largest to the smallest distances about which we have any reliable knowledge. The cosmologist looks out to a cosmic horizon, the farthest distance light could have traveled since the universe became transparent to light over ten billion years ago, while the elementary particle physicist explores distances much smaller than an atomic nucleus. Yet our standard models really work—they allow us to make numerical predictions of high precision, which turn out to agree with observation.

Up to a point the stories of cosmology and particle physics can be told separately. In the end, though, they will come together.

More Fun with Lenz's Law

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You need to a flashplayer enabled browser to view this YouTube video

I’ve linked to videos showing the effect before, but it’s still cool. I notice he spins the magnet — that gives an even faster change to the magnetic field, and enhances the braking beyond what simply dropping it would do. I looked at the effect with a coil, by measuring the induced voltage some time back.

The Game Will Be Over in Two Minutes

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As many of us know, the last “two minutes” of any sporting event can last far longer than that. And, as the joke goes, “I’ll just be a minute shopping for clothes” is similarly distorted.

The Edo Period Daimyo Clock of Unequal Hours

In the Japanese Edo Period (1603-1868), a variable hour system was used(dating back to the 9th century). The day was divided into 12 segments of unequal length. It seemed almost impossible to track unequal periods of time, but Japanese clock-makers devised a remarkable way to keep time in this way. The history of Japanese advances in mechanical timekeeping is indeed fascinating.

Wow. I had no idea.

Physics in the News

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Dry ice bombs were in the news, with two having gone off at LAX. A bit of a surprise that these haven’t been on the radar much, seeing as they don’t have a chemical signature that could be sniffed out, and have no moving parts. When they blow is not really controllable, but the mechanism is simple — the ice sublimates and pressure builds up. Since a mole of an ideal gas wants to take up 22.4L at STP, while the solid takes up negligible volume. Since the volume is restricted, the pressure builds as more gas accumulates, until the container fails. Boom.

What Is a Dry-Ice Bomb?

It’s noted that such devices are illegal, but when I ran across a story about a teen getting in trouble for doing this in his backyard a while back, the law was stated (or perhaps paraphrased) in such a way that it would make any carbonated beverage illegal. I have to hope most laws are written better than that. It’s rare, but soda bottles can explode, and small amounts of dry ice in containers can be interesting. Context, i.e. the amount of material, matters, much like how the dose makes the poison.

Piled High and Deep

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I get this question a lot: “Should I go get a PhD?”

I have never seen a convincing case that getting a PhD is something that you need to get if you’re not going to be a prof.

While Joe cites a harsh fact in the conclusion — that a faculty position is what a minority of PhD recipients achieve — I don’t get the above quote. (Others often couple this with the sentiment that not getting a faculty position is failure, which is thankfully absent here) It’s like there’s this great blind spot about research, by most people blogging about research — they imply that it’s all done by university faculty. A great many people do research in government labs (well, not so much now in the US, what with the shutdown and all) and in private industry. I’m not sure what Joe would find convincing. When an announcement asks for a certain level of experience, I suppose technically one could argue that it need not come from graduate school or a post-doc, but that just creates a circular argument about how a person got that experience in the first place.

I’m not a prof, and you’d better believe my job requires a PhD. I know/am acquainted with many people to which this applies.

Quantum Crosswords

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Uncertain Principles: Quantum Crosswords: My TED@NYC Talk

[W]hen we look around us, we see waves in water and particles of rock, and they’re nothing alike. So, what bizarre thought process could make physicists think they’re the same? The answer is surprisingly familiar. We were led to the dual nature of the universe through the same process you follow to solve a crossword puzzle.

I don’t mean dictionaries full of words sorted by length. I’m talking about the puzzle as a whole—those theme clues that run all the way across the grid, and contain a five-word phrase or a dreadful pun. You can’t look those up, and you won’t guess them. Instead, you piece them together a letter at a time from the simpler clues that cross them. If all of those other crossing words fit together in a satisfying way, you can be confident that you’ve also got the right the theme answer.

I think this is an excellent analogy. Like the jigsaw puzzle analogy, it conveys that the bit of science one proposes has to fit in with other science (whether part of a model that’s not being replaced and/or the evidence we have gathered) so if your “word” is the wrong length, it doesn’t matter that it matches that you know that “a” is the third letter. It has to fit in with what we observe to be true. (This, by the way, is where a lot of crackpots fail — they’re so fixated on one specific area of science that they ignore all the other bits with which a new theory must be consistent.)

One could take this a step further and note that you always do the crossword in pencil, because at any time you can get to a part that shows all of the other words around them are wrong, even though they made sense when you first filled them in. But the more the words interlock and are consistent, the more confidence you have that you’re right.

Can’t wait for the book to come out.

Psssst…

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If you follow physics at all you probably already know about the Nobel. In case you’ve been living in a cave, here you go —

Englert and Higgs

Professors Englert and Higgs have every reason to be very proud, but this prize is really a testament to human intellectual curiosity and perseverance. And well deserved, at that.