Blast from the Past

One fun thing about a big move is the uncovering of old gems that would otherwise lie forgotten in an obscure corner of the basement.  Check out this 1978 second edition of Dungeons and Dragons.  (this is before the game became a cliché and genre unto itself).

In the same box, I found a user's guide to "Gamma World" and an entire box of Traveller paraphernalia...
Oh yeah, I gots my nerd bona-fides!

I see with light but I don't see light

I've been teaching light as wave (and then light as a particle) for years, but only last year did the words "We don't actually see light" (as a wave) come out of my mouth.  I then paused and said "but of course seeing light is actually what seeing is".  The class and I looked at each other like we were all deer caught in the headlights.  I think we were all on the same page at that moment in the classroom, but it is a bit linguistically problematic, isn't it?

Every year, at least one student will ask a question that reveals that age-old misconception that comes from our describing light as a transverse wave:  they are trying to picture photons going in a wave-like path on their way from source to sink.  Adding to, not helping this easy-to-make mistake is the classic picture of light as an propagating electric & magnetic field:

Look - there's stuff going up & down  (& sideways!).  This is what we show the students to justify calling it a transverse wave.  But, nothing is actually "going" up or down.  Those arrows represent field intensities getting bigger and smaller (and changing direction) along the central arrow.  This picture assume a relatively sophisticated understanding of vector fields which first year physics student don't have.

A picture is worth a thousand words, but what if 500 hundred of those words are the wrong words?

Nerd Music

Wow!  Music videos that leaves me feeling like I understand the Higgs Boson and String Theory just  a tiny bit more than before!