“Is it very much more exciting to discover we’re on a ball, half of us sticking upside down, it’s spinning around in space, there’s a mysterious force which holds us on, it’s going around a great big glob of gas that’s burning, fueled by a fire that’s completely different than any fire we can make, well now we can make that fire, nuclear fire. That’s much more exciting story to many people than the tales which other people used to make up who worried about the universe, that we were living on the back of a turtle or something like that. They were wonderful stories, but the truth is so much more remarkable, and so what’s the pleasure in physics is that to me is that it’s revealed the truth is so remarkable, so amazing.”—The Feynman Series (part 3) - Curiosity - YouTube
China is more and more becoming that crazy uncle who doesn’t know what to do with his time. And soon it’ll be that crazy rich uncle who doesn’t know what to do with his money. I can’t wait to see this outcome!
A couple months ago I decided to replace my 90’s era racquet with something new and shiny. It very quickly became an overwhelming process. Head, by itself, has two dozen different racquets in the YOUTEK line, in addition to its older and lower end technologies. And that’s just one company — there are half a dozen well known brands, each with the same bewildering array of options, and another dozen lesser known companies of competitive quality.
What’s a player to do?
One thing I noticed was that many of the racquets have player sponsors. This led me to believe that the racquet makers can not differentiate between their products at a technical level, and thus they are forced to use celebrity endorsements to sell their goods. Want to play like Federer? Buy a Wilson. Want to play like Nadal? Buy a Babolat.
I posed this question to Tyler Cowen in an email, and his response (in its entirety):
Likely so, yes…
I pored through Tennis Warehouse reviews, and eventually ended up with the Head YOUTEK IG Speed 18x20, because of mentions on how customizable the racquet is. You can apparently alter how a racquet feels by adding weights, changing grips, and using different strings.
And then a bunch of articles about co-poly strings on the pro circuit got me thinking about the physics of tennis and whether or not anybody without a profit motive had actually studied the millions of little knobs (frame stiffness, head balance, string tension, string composition, etc) that are tweakable. That led me to Technical Tennis, a fascinating, though admittedly sometimes dry book on the physics of tennis.
Much of the book rings true to me, but it is contrary to popular advice about racquets and strings. It is a liberating book, because the big point is that not much of the racquet and string characteristics actually matter. The technology changes the feel, but as long as you roughly get the weight and head size right, everything else is subjective and does not affect performance.
The most important bits are, in my opinion:
A wide head racquet is more stable. You can simulate this with a smaller head racquet by placing weight at the 3 and 9 o’clock positions.
Weight slows swing speed, but increases rebound power. In the end, the two balance each other out and you should go for the racquet that feels the most natural.
A drop in string tension, contrary to popular belief, does not materially increase power. A difference in 10 lbs of tension requires a change in swing speed of only 1.4 mph in order to compensate for the change in rebound speed. Newly strung strings regularly drop 10 lbs in tension within just a few hours of play.
Rather, string tension affects rebound angle. A lower tension causes the ball to bounce off the strings at a greater angle. A difference of just a degree or so can direct the ball a few feet away from where it might have landed at another tension, thus the illusion of power. Lower tensions tend to rebound outwards towards the back of the court, and higher tensions tend to rebound inwards towards the net.
Note this is easily compensated for by changing your grip. I have always suspected that players who string at lower tensions tend to have more western grips (in essence, they’re aiming lower).
String tension also affects the sound on impact. In an experiment with pro players presented with identical racquets strung at different tensions, those wearing ear plugs did worse than guessing at which racquet was which.
In the end, my advice is this: do not worry about performance, and buy the racquet that makes you happiest. For some, this might mean finding a comfortable racquet. For others, it might be a celebrity endorsement, or even the color of the racquet (I think the look of racquets for the most part is atrocious).
Final note. I’ve only talked about the racquet and string characteristics mentioned in Technical Tennis, but the book contains all sorts of other physics about surfaces, swing mechanics, and other important aspects of the game. Highly recommended.
“This reminds me of the early days of the internet, when phone number lookup sites began appearing. Before then, everybody’s number was public information, published in your local telephone book. You had to at least know what city someone lived in to find their number. But then someone built a website that took all of this public information and aggregated it into a single database, and all of a sudden it was easy to find everyone’s phone number *and* location. There was no extra information leaked here, but it was somehow unnerving, and I’m guessing it destroyed the phone book industry. Who lists their number now? Similarly, Timeline doesn’t provide any more information than was already available on Facebook, but it just does it in such a way that it’s somehow creepy.”—A thought of mine on Facebook’s Timeline, posted on Facbeook.
My experience with Python web frameworks has run a little backwards. I started off by building my own, then moved on to Paste and WSGI components, web.py, Tornado, and finally Django. At S7, we’ve settled on a combination of Tornado and Django, though Tornado may get usurped by something built internally, and there is still exists some healthy skepticism of Django.
There are many obvious reasons for using a large framework such as Django, and some not so obvious. The obvious are listed under their feature set, and I’m not going to talk about that.
The less obvious, but more salient points in my opinion are:
Understood by a large number of people.
Designed by experienced engineers.
Maintained by the community.
Documentation and maintenance effort are generally under allocated, and so the scope of a framework that you might build internally is a direct function of the amount of resources you can devote to it. Given the size of the Django community, it’s unlikely you’d be able to build, document, and maintain a framework of the same scope. And you shouldn’t — because it’s unlikely the choice in framework would vastly affect an engineer’s productivity anyway.
Django has also made many design decisions that a less experienced engineer may botch. This is an especially important problem to avoid if you are a company of young hotshot programmers. There is a tendency to build everything custom. Like cooking, you may know what the ingredients are, but you are not guaranteed that the food is as good or nutritious.
Facebook Devs Just Cost The World Millions Of Dollars In Lost Productivity
You know how you can prevent us from hating you? Don’t waste our time.
Facebook recently sent out a few changes to their comment plugin system. I’ll spare everyone the details, but the upshot is that for pages that use their old system but currently have no comments, they throw an annoying warning message onto your page for all users to see that the site needs to upgrade the comment plugin.
Every time Facebook makes some change like this, suppose it takes half an hour of a developer’s time to fix the problem (gross underestimate). Also suppose that the value of an hour of a developer’s time is $100 (another gross underestimate). Suppose also that there are 50,000 websites that use Facebook comments (yet another gross underestimate). The cost of upgrading that stupid little Facebook comment plugin is up to at least $2.5 million. This is likely an underestimate of one, maybe two orders of magnitude.
Keep up the good work, guys!
(This reminds me my old office, where people would inevitably wait for long periods of time in the lobby. I estimated the value of lost productivity.)
“Tchaikowsky died of colon cancer at the age of 46 in Oxford. In his will he left his body to medical research, and donated his skull to the Royal Shakespeare Company, asking that it be used as a prop on stage. Tchaikowsky hoped that his skull would be used for the skull of Yorick in productions of Hamlet. For many years, no actor or director felt comfortable using a real skull in performances, although it was occasionally used in rehearsals. In 2008, the skull was finally held by David Tennant in a series of performances of Hamlet at the Courtyard Theatre, Stratford-upon-Avon. After the use of Tchaikowsky’s skull was revealed in the press, this production of Hamlet moved to the West End and the RSC announced that they would no longer use Tchaikowsky’s skull (a spokesman said that it would be “too distracting for the audience”). However, this was a deception; in fact, the skull was used throughout the production’s West End run, and in a subsequent television adaptation broadcast on BBC2. Director Gregory Doran said, “Andre Tchaikowsky’s skull was a very important part of our production of Hamlet, and despite all the hype about him, he meant a great deal to the company.””—Andre Tchaikowsky - Wikipedia, the free encyclopedia