Built on Facts

Not too many decades ago, some scientists discovered that certain materials would conduct electricity perfectly if you got them cold enough. Not just conduct electricity well - those materials actually conduct with zero resistance. Appropriately, the phenomenon was named superconductivity.
The problem for making thus useful is that you have to make these materials [...]

[Read more →]

We live in a nice, classical world. We can tell where we are and how fast we’re going. We can spin things around at whatever speeds we feel like, and if we throw something through the air we can predict where it’s going to go.
Quantum mechanically, however, things are a lot fuzzier. [...]

[Read more →]

Ever wondered why nobody thought up relativity until Einstein in 1905? Like quantum mechanics, its effects are pretty hard to notice in the everyday world. Here’s a tiny example. According to the theory of relativity, time will pass more slowly for a moving object as measured by someone standing still. Why [...]

[Read more →]

Are there more stars in the universe or atoms in a cup of coffee?
There’s a lot of stars in the universe, but then again atoms are really tiny. As it turns out, there’s very roughly about 100 billion billion stars in the observable universe. In scientific notation, that’s about 1022 stars. It’s [...]

[Read more →]

The divergence theorem? Gauss’ law? If you’ve had college physics, at least the second is familiar to you. Now those two things are really fascinating, and I’m going to put a math-lite layman’s explanation in a future post. But hey, it’s spring semester finals time and that means all you people [...]

[Read more →]

The speed of light is both one of the most famous and one of the most fundamental quantities in physics. Even people who don’t really follow physics can often tell you how fast it is. 186,000 miles per second is the figure usually quoted. We know that the speed of light is [...]

[Read more →]

Many of my students had their final exams today. In the weeks leading up to the exam, we reviewed by doing homework problems and working final exams from previous years. Here’s one of the questions:
Protons of velocity 5×106 m/s are moving perpendicular to electric and magnetic fields which are crossed at right angles [...]

[Read more →]

In every branch of knowledge the progress is proportional to the amount of facts on which to build, and therefore to the facility of obtaining data.
- James Clerk Maxwell
Maxwell was of course one of the greatest physicists who ever lived.  Best known for formulating the classical theory of electromagnetism, he also contributed enormously to our [...]

[Read more →]