## A Math Prof, A Psych Prof, And A Mysterious Black Dog

Once upon a time, a mathematics professor (whom I shall call Professor M) from a North American university was regaling a small group of professors and graduate students with some anecdotes concerning a psychology professor (whom I shall call Professor P) and a mysterious black dog (whom I shall call B). A that time, the … Read more

## What Is A Scientific Theory?

How does science work? (At least in the case of physics and other mathematical sciences.) I touched on this subject before (in a post entitled Does Nature “Obey” The Laws Of Physics?), but I would like to take a more general perspective here. So how does science work? First you observe the world, and you … Read more

## Art And Mathematics

My friend Mary sent me this link to a video by Vi Hart about why $\pi$ is wrong. The video is funny, and the rest of her site is wonderful, engaging, and worth checking out. There is a nice article about her in the New York Times. The originator of the “$\pi$ is wrong” idea … Read more

## On Choosing The Best Units

Update (21 March 2011): A great version of the Gimli glider story is here. In 1983, an Air Canada plane ran out of fuel on a scheduled flight. Running out of fuel is a very unusual situation for a modern airline; the problem here was an error in converting units between the Imperial system and … Read more

## Time Variation Of Pi

Since at least as far back as the work of Dirac in 1937 (see here), there has been discussion about whether the fundamental constants of physics might vary with time. Unfortunately, some of these ideas have been stretched by young-earth creationists, in a completely unscientific way, to bolster their hypothesis that the universe was created … Read more

## Why Radian Measure Makes Life Easier In Mathematics And Physics

The two most commonly used measures for angles are degrees and radians. There are 360 degrees in a full circle (a right angle is 90 degrees), and $2\pi$ radians in a full circle (there are $\pi/2$ radians in a right angle), so there are about 57 degrees in a radian. Students typically learn about degrees … Read more

## Is Lenz’s Law Just An Instance Of Newton’s Third Law?

The short answer is, “Yes.” The longer answer exemplifies one of the lovely things about physics: its internal unity, and the fact that a few basic principles manifest in a plethora of circumstances. And one of the typical shortcomings of our textbooks (and by extension our lectures). For me, this was one of the attractions … Read more

## Does Nature “Obey” The Laws of Physics?

Today I’d like to discuss a pet peeve of mine. In many physics textbooks, one reads phrases such as: a certain physical system obeys a certain law of physics Here’s an example taken from page 147 of Chemical Principles, by Steven S. Zumdahl, Cengage, 2009 (although I am not trying to single out this author … Read more

## Diane Ravitch On The Failure Of “No Child Left Behind”

On March 3rd, Diane Ravitch appeared on The Daily Show to promote her recent book, The Death and Life of the Great American School System (a New York Times review is here). It’s a great episode, and worth watching (here if you live in the U.S., here if you live in Canada). Ms. Ravitch discusses … Read more

## Foldit: A Computer Game That Helps Advance Protein Science

Foldit is a joint research project of the University of Washington‘s departments of Biochemistry and Computer Science and Engineering. The basic idea is to enlist members of the public to play an online protein-folding game. The data from the human players is added to a database that will help improve computer protein-folding algorithms. Humans are … Read more