Standard Deviations From the Beaten Path

If you’re a huge nerd, you’ve probably at least seen Wolfram Alpha. At least once a week or so I stop to play with it to see if I can get it to do anything cool. So it can tell you where most of the worlds Portuguese speakers live and give you a side-by-side comparison of the population, land area, and GDP of South Africa and Lesotho. Both of those are extremely cool, but this morning I found a new one. Just in case you ever wanted to know what would happen if you rolled two 12-sided dice (since 3rd Ed. D&D will probably never give you the opportunity) it will now give you the mean value and a histogram! It works for an number of dice with any number of sides. Even the mysteriously fair 5-sider. There seems to have been a large gaming-related “expansion” or something to the site, because it will also tell you the probability of a full house.

This kind of thing could probably entertain me for hours.

So I’m going to do some music-related mostly non-science blathering. First, a new Dream Theater album released last week. They are one of my all-time favorite acts, so whether you’re into progressive metal or not, I recommend at least giving them a test listen. I haven’t heard the album yet, as the USPS is taking its dear sweet time with the three disk collectors edition I pre-ordered. Also, I really hope I make it to a show in the inevitable tour in support of the new album.

In terms of other musicians I like, George Hrab is really cool. A few weeks back I thought why not ask this science savvy musician what he finds curious about the physics of music? And cool guy that he is, he responded. This was so cool, yet so utterly terrifying at the same time. I’d like to solve this problem he’s proposed.

One issue. I don’t know what it means. I’m a hobby musician. Heck, I couldn’t read sheet music under threat of torture. So if I could get an explanation of tempered tuning for someone who fled from piano lessons like frightened forest creatures from a fire I will do my best to resolve the mystery that is how a fretted instrument like a guitar can play in tune with a tempered instrument like a piano.

I caught this video on the youtubes this morning. Richard Wiseman is an all around pretty cool guy, from what I’ve seen of him. In this video, he’s exploiting the “blind spot” in the human eye to make his head seem to disappear. He passes a long black rod over his face, which appears continuous. This is because your brain is very clever at compensating for the imperfect nature of your eye. Pretty amazing.

This also reminds me of a wonderful quote from Massimo Pigliucci regarding the fact that squid and octopi don’t have the same problems since they evolved eyes separately from us. He said, “the only possible conclusions to this evidence are that God didn’t design the eye, or he’s pretty sloppy and not worthy of our unconditional admiration, or God likes squids a lot better than humans.”

I get more hits from Google searches about electric guitar physics than anything else. So that seems to be a subject in high demand. If you haven’t seen my first post on the topic check it out. Currently, I’d like to talk about why notes played closer to the bridge of a guitar sound “dirty”. If you’ve never witnessed this phenomenon, I’ll try to have some examples prepared.

Guitar strings, like any string fixed at both ends, have resonant modes corresponding to particular energies and frequencies. The simplest and lowest energy modes have the fewest crests, so the lowest energy mode for a string is when the center of the string moves up and down. It is the tendency for things to fall into their lowest energy states, so it is this mode which produces the note you hear when a string is plucked.

Higher energy modes displace the string from equilibrium in more locations than the middle. So if you pluck a guitar string farther from its center, you introduce more of these modes corresponding to higher frequencies. A listener will still identify the note being played as the lowest energy resonant frequency, but there will be other higher frequencies audible at lower relative volume.

I’ve modeled this behavior mathematically so we can see it graphically. Waves follow a differential equation called the wave equation, which is generally . This equation has a well understood solution, all we need to do is provide initial and boundary conditions. I’ve imagined a string fixed at both ends with a length of one unit. I’ve also decided that we’ll just pull one point on the string some distance away from equilibrium.

Plucked in the center.

Plucked 0.25 from the nearest fixed end.

Plucked 0.05 from the nearest fixed end.

I’ve written all of this up in a Python 2.6 script using the SciPy library, which I’ll provide you with to mess around with on your own (I think it’s fun, anyway). It will take two command line arguments (both optional), the first specifies the place to pluck the string, the second how far to pull it. Defaults are 0.5 and 0.05.

I’ve produced three graphs which show the initial conditions, the displacement of the string as a function of time at a fixed point on the string (0.75, since this is a fairly reasonable place for a pickup to be along an electric guitar), and a Fourier transform of the “signal” in the previous cell for plucks in three different locations. The important thing here is the result of the FFT.

A Fourier transform is means of going from a description of something’s position in time to a description of the frequencies which describe that motion in time. What it shows us here is that the oscillations in the string have higher frequency components when the string is plucked closer to a fixed endpoint. The scale on the y-axis is arbitrary and is just a way of judging relative prevalence of each frequency on the x-axis (also arbitrary). As mentioned before, this is due to higher energy harmonic modes being stimulated when the string is plucked further from its center. This is why the same guitar can make so many different sounds from clean to twangy!

There’s a video up (a couple of videos, even) of Buzz Aldrin, the second man on the moon, rapping with Snoop Dogg. See the song Rocket Experience, and the making of video. I grew up on books about the space race. I really should go back and re-read some of them, because that is just one of those few things the sheer awesomeness of which does not attenuate with age. I’m far too myopic and prone to motion sickness to ever go into space myself, but I’ll take studying things in space for a living.

Hey folks! In my head there have been big changes around here. Now maybe those changes will be converted to actual readable content. So I’ve hinted that I want to make this space less dedicated to exclusively science. My original dream of this being slick and professional is just going to be hindrance to me actually using it. Moreover, I’ve realized the value my being personal might have to some people reading. Particularly, Mark Chu-Carroll at Good Math, Bad Math brought up Mental Illness.

So I’ve said it once before, but I’ve been diagnosed with bipolar disorder. It’s not something I want to blog about, because it’s something I want to separate from my identity as much as possible. I don’t want to talk about what’s happened to me because of my disorder, or how it’s affected my education, my relationships, or my career. There are mental health blogs out there that I consume regularly, but I don’t want to and can’t be one of them. I want most of my personal life to remain personal, and there is little that is more private to me than the details of my mental health.

So why bring it up at all? Because someone might want to know that you can live with mental illness and have a thriving life full of passions and interests. Science is not an easy career, and physics especially is competitive and draining. But I can do it–I am doing it. And I want that knowledge to give somebody hope. So I promise more science, more math, more games, more commentary and reviews, and I can’t promise, but I can casually mention the serious, solid possibility of a co-blogger moving in in the next month or so. I’ll let her introduce herself when she gets here.

I’m reluctant to admit it (I’m not sure why), but I do value personal content in the blogs I read. My relationship with science is more complicated than what I do in the lab all day, and my online presence should reflect that. So I’ll try to be here more often, even if I don’t feel like what I have to say is especially profound. Hopefully I’ll see you around.

Hi! I really want to do something worthwhile with this space, regardless of whether on not these words are being read or not. At the beginning of this month there was a deluge of new students working in the lab, but now that my manegarial duties have subsided, I really want to talk about some science outsiside the strict arena of my own employment. Definitely need more guitar physics (and music physics, in general, actually), and any thoughts, questions, or comments would be welcome on that front.

I still want a co-blogger, who will at least help me put content here at least slightly more consistently in the hopes that people won’t strike STDEV from their RSS feed readers. Actually today I popped the questions to one of my top picks for a candidate co-blogger, and maybe I’ll hear back shortly.

I’ve actually got some research related funness I would joyously go on and on about. Namely, the GPS system is really cool and useful for we sciencey types. In more generic nerd-related happenings I’m building a quasi Beowulf cluster out of some desktops in the lab in the hopse that we’ll be able to distribute our computationally intensive simulations. And if something can be a meme on Slashdot, it must be cool, right?

I’ve read advice before (which I would link to if I could find a link) that in writing a skeptical blog the best way to go is to choose the most specialized, specific topic you can. I don’t have that kind of patience. The “whimsical adventures” bit in my tagline was originally my way of escaping the confines of a purely straight-up science and skepticism blog, but I still wanted to keep it reasonably narrow.

Well I’m going to loosen myself even further, I think. Because even the ostensibly specialized blogs have such a low signal-to-noise ratio, that I have to subscribe to ten RSS feeds on a particular topic to get that many posts I actually finish reading a day. To be entirely honest, my main motivation for starting to blog myself was that the signal-to-noise on comment threads is so bad, they are almost universally unreadable. On a popular blog, the comments unfailingly degrade into people repeating what other people have already said ad nauseum. I think some people award themselves participation points based on their post count rather than on the actual content.

Which is not to say I think they should stop posting. I’m just saying that I’m not reading what they’re posting–and I am definitely not following them on Twitter, which I think might be the noisiest information channel currently available on the internet. It’s nominally a micro-blogging tool, but is by and large used as an instant messaging tool shipped out to anyone who’s listening. The result is that even if I want to follow some of my dear friends back home in Indiana, all of the information I actually care about will be drowned out in their half of a conversation about cow tipping with people I don’t know.

So we’ll see, maybe I’ll one day become popular and have to eat those words. For the time being, I’m going to direct anyone who cares to my sidebar if they’d like to check out the non-science links I’m adding to my blog roll. This will be a bit slow as WordPress doesn’t seem to provide the specific tools I want to make this process feel like less of a chore. Also, I still want one co-blogger, and I actually have a couple of candidates who I should probably just ask if they’d like to do it.

I more or less grew up on science fiction. Actually, I pretty much remember how it started. I was sitting outside at school reading Michael Crichton’s The Andromeda Strain. My english teacher asked me if I liked reading science fiction, which was something I’d never really stopped to consider. First I actually had to figure out what science fiction was. I had a vague idea what it wasn’t, but was pleased to discover that it had “Grand Masters,” so I could probably read them to dev elop a better idea of what science fiction was.

From here things probably get pretty predictable. I read Arthur C. Clarke and Isaac Asimov–everything by these two authors I could find on the shelf of Barnes & Noble. I sort of knew there was more, but I’d have to order it and I loved to just browse at the bookstore and pick something out that way. So I browsed my way into reading almost the entire Star Wars Expanded Universe series of novels. And having gotten through those, I started looking for authors of Star Wars books I liked in the rest of the stacks.

This led me first to Timothy Zahn, who wrote a fantastic story called A Coming of Age that I found at the local library. Zahn’s other pre-Star Wars works were quite good, but the real gem that I found in my post-Star Wars epoch was a book by Vonda McIntyre called Dreamsnake. This was my first, completely unassuming, foray into feminist science fiction. I can’t do justice to the emotions I felt reading through that book, but it opened up the longest continuous obsession with a genre of fiction in my life to date. To this day Dreamsnake sits next to Ursula K. LeGuin’s The Left Hand of Darkness.

Feminist science fiction seems to have a small, dedicated community surrounding it. I’ve been using feministsf.org as a reference for what books to look for at the library or used book store for the better part of a decade. While that search is exciting, I still find it mystifying how so many people have come upon authors like Joanna Russ or Suzy McKee Charnas when finding copies of their books is so difficult. There are many central authors of feminist science fiction whom I have never read on account of never having come upon a book of theirs.

Which isn’t so say the handful of books available in your local bookseller aren’t worth reading. Ursula K. LeGuin is still my favorite author, hands down. Octavia Butler is available from time to time, as well, and the last Vonda McIntyre book was easy to find back in 1997. But even the new feminist science fiction is unseen. Every year the Tiptree Award goes to a book for exploring sex and gender in some exceptional way, and there’s usually not a book on the list on the shelf at Borders.

So what I want to know, is how do the people who nominate books for the Tiptree Award find them? In world that’s any fair at all, one should not have to be a member of the Secret Feminist Cabal to hear about these amazing books when they hit publication. I’ve got plenty of classics left to read, but I want to feel in-touch with the community. Reading the Feminist SF Blog only goes so far. I want a new book in one hand and a glass of iced tea in the other and a weekend spent sitting on my porch reading.

Earlier in the week there was an interesting discussion going on at Feministing that I feel like I should say something about. There’s a summary Community Blog Round-Up and probably the most relevant-to-my-thoughts post here.

So I’m a feminist. I could go on in long winded fashion about what feminism means to me, but I honestly don’t find that important right now. The nature of the discussion is: are male feminists over or under rated? I don’t know that I can address that question either, actually. But I can say quite definitively for myself, though, that I’d rather not be rated at all.

I’m just doing what I can, which for the most part is just engaging in personal discussion with my friends and those around me. I don’t want a cookie or recognition any more than I want to be admonished for not doing more. If I get out of line, fail to recognize my own privilege (which still exists, even if I am wearing a “This is what a feminist looks like.” button), I’d like a reminder. But I really do think most people can spend their time better than by either talking up or talking down male participation in feminism.