Today I rediscovered radiolab (from WNYC).  It’s an amazing radio show that has an intense and interesting curiosity about all things in the world, written and hosted by people that are similarly intense and interested.

A recent show told us about a video on… parabolas.  See the video here. Sure some of the shapes featured are not parabolas, but it’s the intro when Steve Strogatz is speaking that’s most important.  Among the quotes from Strogatz that I like best, when describing how a pendulum (like on a grandfather clock) has a relationship between the length and the time of a complete swing: ...this really gave me the creeps.  because it was as if this inanimate thing, this pendulum, knew algebra.  how could this thing swinging back and forth know something about parabolas?  or how could that be built-in?  It was in that moment that I understood that there was a ‘law of nature’.

Why is it that of all the functions we know, the ones we first learn in algebra class are so important that they describe such a diverse range of phenomena?  Isn’t it both creepy and amazing that there is this underlying order to the behavior of objects?  Besides the pendulum, which you will hopefully see later in the semester or a further physics course, we see parabolas in the projectile motion equations.  Why parabolas?  Why not y = t^3 or t^(1/3) like BM said on Thursday in class, or any other functional dependence for that matter?  Why not acceleration in the x direction as well as y?

Images compiled from Will Hoffman’s Parabolas (etc.)

This week we saw some of the properties of fiber optic cables and talked about CCDs.  Both of these objects are the subject of the 2009 Nobel Prize in Physics.  More can be found on the physics and prizes at the Nobel website.

The fiber optic cable has been known for over 100 years in various forms — not always useful.  The first form talked about in the Nobel citation was as a “light fountain” (see below for an old illustration of one; also see wikipedia’s article).  Both fiber optics and this column of water rely on a property of surfaces that allows light to continuously reflect in the denser material called total internal reflection (which is easy to demonstrate in an aquarium).  You will learn about optics in the second semester of physics.

CCDs are an amazingly ubiquitous invention as well.  As we talked about in class, nearly everyone has one in their phone if there is a camera.  CCDs rely on concepts in modern physics such as the photoelectric effect in order to work — that is, light that hits a CCD surface causes electrons to discharge.  In the Nobel’s more elegant verbiage: A CCD records “a scene by accumulating light-induced charges over its semiconductor surface, and by transporting them to be read out at the edge of the light sensitive area.”  This allows you to take your digital photographs!