Experiment vs. Theory: The Eternal Debate
Bottom line: we have lasers, with or without the sharks.
That’s something you can show off on a tour of the department and it’s guaranteed to make an impression on prospective students and parents.
From my perspective, it’s also something you can show off to admirals and generals and civilian upper-level cogs. So I’ve got that going for me, which is nice.
It’s October, and that means it’s the time of year that the science blogging Donors Choose challenge gets underway. I see that among the blogs I regularly read, Cosmic Variance, Dot Physics and Uncertain Principles are all participating in the organized challenge for their respective blogging organizations. Please consider picking one (or via the Colbert challenge) and making a donation.
Update: add Bad Astronomy to the list
The Big Picture: The National Ignition facility
“Creating a miniature star on Earth” is the goal of the National Ignition Facility (NIF), home to the world’s largest and highest-energy laser in Livermore, California. On September 29th, 2010, the NIF completed its first integrated ignition experiment, where it focused its 192 lasers on a small cylinder housing a tiny frozen capsule containing hydrogen fuel, briefly bombarding it with 1 megajoule of laser energy. The experiment was the latest in a series of tests leading to a hoped-for “ignition”, where the nuclei of the atoms of the fuel inside the target capsule are made to fuse together releasing tremendous energy – potentially more energy than was put in to start the initial reaction, becoming a valuable power source. The NIF has cost over $3.5 billion since 1997 and is a part of the federally funded Lawrence Livermore National Laboratory. Scientists at NIF say they hope to achieve fusion by 2012.
Turn on your kitchen tap and the steady stream of water will spread out into a thin circular disc when it hits the sink. This disc has an unusual property: it is surrounded by a circular “lip”, where the height of the water changes suddenly.
This so-called hydraulic jump has puzzled physicists for at least a hundred years (John Strutt, otherwise known as Lord Rayleigh, published the first mathematical description of the phenomenon in 1914). These kinds of hydrodynamic problems are notoriously difficult to tackle.
A map two-fer: The true size of Africa.
Flickr: Race and ethnicity maps
Red is White, Blue is Black, Green is Asian, Orange is Hispanic, Gray is Other, and each dot is 25 people. Data from Census 2000.
I would have gone with white is white and black is black, and put it all on a teal background, but the Avatar aliens would have been excluded…
The Difference Engine: Dubious security
Authentication of a person is usually based on one of three things: something the person knows, such as a password; something physical the person possesses, like an actual key or token; or something about the person’s appearance or behaviour. Biometric authentication relies on the third approach. Its advantage is that, unlike a password or a token, it can work without active input from the user. That makes it both convenient and efficient: there is nothing to carry, forget or lose.
The downside is that biometric screening can also work without the user’s co-operation or even knowledge. Covert identification may be a boon when screening for terrorists or criminals, but it raises serious concerns for innocent individuals. Biometric identification can even invite violence. A motorist in Germany had a finger chopped off by thieves seeking to steal his exotic car, which used a fingerprint reader instead of a conventional door lock.
Plus, you can also fake out scanners with digits made from play-doh or gelatin (after which, especially for the latter, you could eat the evidence). Still waiting for that one to show up on CSI.
Physics: Don’t Panic! 10 Steps to Solving (Most) Physics Problems
Don’t panic.
Physical equations didn’t just land on scientists from the sky, all wrapped up nicely in mathematical formulation. They are derived from physical properties, and they are all interconnected. In most physics problems, there is more than one way to reach a solution, often meaning that more than one equation can work. In fact, in the vast majority of questions, no matter what equation you use – assuming that it is relevant to the subject matter, and that you insert the proper variables – you will reach a solution.
