Pop Physics

7.4 The Eye

Liam — Wed, 27 May 2015 15:55:29 +0000

Critical Questions: What does an eye do, and how does it work? How do we achieve depth perception? The complexity of the eye is frequently pointed to by creationists as proof that evolution didn’t happen, because it cannot possibly have resulted in such improbably effective organs. The argument goes something like this: “Just look at ... Read more

7.3 Lenses, Mirrors, Cameras, and Telescopes

Liam — Fri, 08 May 2015 21:51:07 +0000

Critical Questions: What does a lens do? Why do things look bigger or smaller or otherwise distorted when seen through a lens? Lenses have been around for a very long time. This isn’t too suprising – as soon as humans starting working with glass, it’s not hard to imagine someone looking through a curved piece ... Read more

7.2 Light

Liam — Thu, 09 Apr 2015 16:50:44 +0000

Critical Questions: The main reason that light has always been so hard to figure out is that it follows its own rules. For example, we’re used to things having mass. People, ferrets, churches, very small rocks – all are made up of matter and thus do things like resist acceleration (according to Newton’s Second Law) and create gravitational fields. Light, on the other hand, has no mass. It’…

Source

7.1 Introduction to Light and Optics

Liam — Fri, 20 Mar 2015 20:15:53 +0000

If you want to really understand just how weird light is, you have to imagine the perspective of someone from a long, long time ago. Why not choose, for example, a farmer in Southeast Asia a few thousand years ago. Put yourself into the farmer’s shoes – unless this is a barefoot farmer, in which ... Read more

6.5 The Doppler Effect

Liam — Mon, 23 Feb 2015 21:52:38 +0000

Critical Questions: I’d like you to do me a favour. This is especially important if you’re in a public place, surrounded by lots of strangers. I’d like you to imitate, out loud and at a significant volume, the sound of a racecar going by. The noise you made probably sounded something like, “weeeeeeeeEEEEEOOOOOOOooooo”. It’s a fairly common sound effect, one most people can perform even…

Source

6.4 Resonance

Liam — Sat, 07 Feb 2015 16:36:56 +0000

Critical Questions: In the same way that it must be illegal to talk about buoyancy without telling the story of Archimedes and the crown, everyone who teaches resonance brings up the Tacoma Narrows Bridge at one point or another. This is probably because there is some cool old black-and-white footage of the bridge swaying and rippling impossibly in a stiff breeze, as follows: It’s clear…

Source

6.3 Sound

Liam — Thu, 27 Nov 2014 03:35:15 +0000

Critical Questions: The well-known Zen koan asks: if a tree falls in the forest, does it make a sound? If you’re ok with the idea of not reaching enlightenment just now, physics can give a rather bland answer to the question. Sound is nothing more than vibrating air. When you speak, for example, your vocal cords are moving rapidly back and forth, striking air molecules with every forward…

Source

6.2 Waves

Liam — Tue, 11 Nov 2014 02:46:34 +0000

Critical Questions: There’s a story I heard somewhere – I have no idea whether it’s true or not, but I like it anyway. The story is that a group of people somewhere in the world developed a language that had an interesting way of referring to water waves. Instead of pointing at the ocean and saying, “Hey look, there’s a wave,” they would point at the ocean and say, “There is waving.

Source

6.1 Introduction to Waves and Sound

Liam — Sun, 19 Oct 2014 21:03:46 +0000

There is a secret about waves. It is the kind of secret that, if you fully understand it and its implications, may well blow your mind and leave you scribbling paranoid manifestos on attic walls. Or worse, you might only think you understand this secret, and go off and make some horrible and misleading movie ... Read more

To Stir, Or Not To Stir

Liam — Wed, 13 Nov 2013 16:44:34 +0000

In my physics undergrad, we had one prof who seemed a bit strange. Actually, being only a bit strange seems something of an accomplishment for a physics professor, as most of them ran the gamut from odd to unintelligibly bizarre. But the one I’m talking about here was a younger guy who taught us about thermodynamics. He was odd in a number of ways, but one sticks out in my memory: one day…

Source