Words, Episode 6: “… 2000 times as small …”

I’ve been reading the very fine book Superconductivity: A Very Short Introduction, by Stephen Blundell, about which I’ll have more to say in a subsequent post. The book is very well written, with only a very few editorial infelicities in the book, the most striking of which is the following phrase, which appears on page … Read more

Why Does A Propane Torch Get Cold When Used? Updated, With Refrigerators

I was fixing a leaky water pipe in my garage yesterday, and so I had occasion to use a propane torch to heat up the pipe and melt the solder into the joint. It’s not something I do often, but I do remember learning from my father (who was experienced in plumbing, and was somewhat … Read more

A Practical Use For Logarithms, Part 2: How We Multiplied Large Numbers 40 Years Ago, And How Integral Transforms Use The Same Basic Idea

(Click here for Part 1.) A common argument for the use of technology is that it frees students from doing boring, tedious calculations, and they can focus attention on more interesting and stimulating conceptual matters. This is wrong. Mastering “tedious” calculations frequently goes hand-in-hand with a deep connection with important mathematical ideas. And that is … Read more

Teaching Critical Thinking: An Example From Electricity And Magnetism

As I discussed in this post the other day, I believe that an excellent way to teach critical thinking is to present students with statements that are muddled, garbled, confused, poorly written, or just plain wrong, and instruct them to identify the errors and correct the statements. How can we train students to be critical … Read more

Sense And Nonsense In Elementary Electricity And Magnetism

Today my students wrote the final exam in the first-year university course in electricity and magnetism (+ a two-week introduction to quantum physics at the end of the course) that I taught this past semester. I reproduce the first question on the exam below. Worth 20% of the marks on the exam (each of the … Read more

A Practical Use For Logarithms

What can you do when you have to describe phenomena that extend over many orders of magnitude? One option is to use different units; this is what we typically do in every-day life: We use centimetres or inches to describe distances on our desks, we use feet or yards or metres to quote the dimensions … Read more

Everyone Complains About Taxes, But Who Knows Where They Go?

David Olive writes about an American initiative to help inform citizens about how tax money is spent. By providing freely available information, one hopes that there will be a more sensible discussion about the perilous financial straits in which the American federal government (and many state governments as well) is currently sailing, and more cooperative … Read more

The Probability of Precipitation: What Does it Mean? Part 2, A New Resource

A while back I posted on this topic, starting with my father-in-law’s quirky (but charming) interpretation of probabilities quoted in weather reports, and continuing to discuss the meaning of probability in the context of weather forecasts. I suggested that someone ought to check on the accuracy of such reports, and listed a few resources. There … Read more

Carlsberg Beer, Horseshoes, Luck, And Niels Bohr

Niels Bohr was one of the giants of twentieth-century physics. He and Einstein respected each other very much, but their work habits were just about opposite. Einstein preferred to work with just a single assistant, if at all, whereas Bohr worked very hard to secure funding for an institute of theoretical physics in Denmark. Bohr … Read more

PersonalBrain, A Digital Organization/Mind Mapping/Hyperlinking Tool

I just found out about PersonalBrain, a free software tool that enables one to organize computer files, web pages, and ideas in a mind-map-like structure that is expandable/contractable. A friend told me about it tonight, and said that the online Encyclopedia Britannica uses it to organize its two million plus web pages. I can’t vouch … Read more