July, 2009


29
Jul 09

How Physicists Build a Bridge

Imagine the following, you have a room, twenty stories high and 50 feet across. You want to hang a Foucault Pendulum in this room. Here’s the catch: the ceiling is made of glass and can’t support the pendulum. The only way to hang it is with a cable that traverses the gap between the walls. Now we do have a little something to work with, on the other side of the walls are banks of offices from floors 1 to 20. Furthermore these offices have windows opening on to the room.

This is the situation physicists at Fermilab found themselves in when they wanted to hang a pendulum in Wilson Hall [ picture ]. Now they could call in a construction crew, build scaffolding up twenty stories and just connect the cable like that. Not pretty but it would get the job done. However they wanted something pretty. Firstly, things are a little easier. We don’t actually need to get the heavy duty cable across to begin with, we can start with a lightweight string, and use that to pull across increasingly heavy cables. The Niagara Falls Bridge for example started when a young boy flew a kite across the falls.

Unfortunately  kites don’t work inside. Well maybe we could have someone throw a baseball across the gap with the string pinned to it. Maybe but the physicists were more inspired by the 0 brawn approach: two people go up to 20th story offices, each with a ball of string. They drop the balls (holding on to an end) all the way down to the ground 20 stories below.  A third guy ties the ends together. Wind the string up. voila, we have our bridge.


27
Jul 09

What You Learned About How Asparagus Works Was Probably Wrong

It’s a small quirk of human metabolism that Asparagus makes our urine smell. Due to some research in the 80s we’re now pretty darn sure that the smell is caused by a triage of sulfur containing alkyl compounds citation. But a few decades before scientists pulled out the big guns and nailed down exactly what was causing this phenomenon, they looked at the much simpler question: “Who makes smelly urine?” Observations of the day held that many people met tales of Asparagus Urine with vacant stares, and a few studies revealed that the percentage of people making smelly urine was in the low 40s citation . (This study was done in The UK and would probably yield very different results in other countries.)

So the scientists concluded, this is a polymorphism, different phenotypes existing in the same population. Some people’s digestive tracks produce the malodorous compounds, and some don’t. Simple enough right? I’ve been told they even managed to find the corresponding genotypes, and the correlation they had was great. I heard it got as far as children’s textbooks, before someone pointed out a tiny flaw in the experiment.

The experimenters had been a bit shy in their work. They’d fed people asparagus and asked: “Now does your pee smell?” when they should have asked the more risque: “Does his pee smell?” Had they asked the latter they would have found that ≈40% of people said yes all the time, and  ≈60% said no all the time. Because it turns out that everyone digests asparagus the same way and outputs the same urine, it’s just that not everyone can smell it.


…transforms my chamber-pot into a flask of perfume -Marcel Proust


This post was inspired by an old Daniel Miessler post which surfaced yesterday on Hacker News entitled “ Why Planes Fly: What They Taught You In School Was Wrong .”


26
Jul 09

The Salesman Edward J. Smith

I ran into a representative of The New York Times the other day at lunch. “Holy guacamole.” he said to me from the next table. As he did he put down an archaic looking cellphone signaling to the rest of the cafe that it was okay to start talking again. He immediately began explaining to me that he was in town on business, “We’re seeing if we can’t move papers here (Hyde Park, Chicago). Try to get a few professors to use them in their classes. Have you ever read The Times?”

“Of course, but online.” I said. “I understand that you guys are in trouble these days.”

“Right now our readership is actually going up” he responded “As the smaller papers go out of business their readers become ours. We’re picking up 120,000 subscriptions at a time. But yeah we’re in trouble, this must have been how Edward J. Smith felt.” (I had to look it up too, he was the captain of the Titanic.) “I don’t understand why we’re in trouble, people like to read, you like to read, can you honestly say you do all your reading online?”

Yes I can say that (and I did) . Amongst our generation there’s no question of competition between print and screen. I do everything on my computer and the ease of opening a new tab is something that print will never match. But a sheaf of print was never The Times real product–print simply used to be the cheapest medium for delivering content. These days The Internet is that medium and I think The Times has embraced this (although apparently our guy hasn’t). In fact, their site is a savvy piece of work. But I felt the need to press him further: “What do you guys think about reddit?”

He’d never heard of reddit, and I was appalled, it was like a Coca-Cola employee not having heard of Pepsi. I obligingly explained, trying to conceal my pride at my generations elegant solution. The Time’s content could never beat reddit’s, because reddit’s content included The Time’s, it was a simple subset argument. Finally we got to the question: “So what’s reddit got that we don’t?” Aha, I knew this one cold, reddit’s got its community, its chaotic masses that somehow always float the most interesting bits of The Internet to the top of the home page and have collectively consumed every scrap of sci fi in existence. The New York Times might create brilliant content, but reddit facilitates its consumption and the former, by itself isn’t a business model anymore. Not on the scale The Times needs it to be. This is reddit’s edge.

But it isn’t. The New York Times is pulling in 15 million unique visitors a month (according to compete.com) and reddit’s community won’t beat The Time’s. Anyone who’s anyone reads it. Winston Churchill read it. Try to imagine what his karma would have looked like. The problem is, right now they’re doing nothing to leverage this community, and this is the final nail for print. They don’t need to convince us to read their paper’s or use it in our classes, we already do that, they need to convince us to pay for it. The Times is planning to finally cut off free access and try to sell subscriptions to its online content. If this happens it will be the end of my readership. But if they offer me the option of interacting with their other readers (their staff would be cool as well), who share my interests and have worthwhile opinions, then I’m in. I’m in for double what they’re thinking about asking right now.