Built on Facts

Archives for April, 2010

Physics, Rockets, and Iron Man

I’m not quite convinced Iron Man is entirely realistic. “Proposterous!”, you say, “Hollywood makes its superhero films to near-documentary accuracy!” No, hear me out. Iron Man can fly, using rockets in his hands and feet. We know from the commercials that the suit can in fact fit in a briefcase and be carried around by…

Back in the 1600s science was much less specialized. You didn’t really have biology, chemistry, physics, and even mathematics for that matter as fully separate disciplines. If you did science, you were a “natural philosopher” and that was that. Now even physics by itself could be argued to be about a half-dozen separate disciplines whose…

Laser rifle recoil?

There’s a really snazzy physics blog run out of Cornell called The Virtuosi. Sort of like this blog, they’re big fans of looking at interesting scenarios through the equations of physics. Not long ago, they had an interesting post looking at whether or not laser guns would have recoil. I’m not going to duplicate the…

Relativity from a Flashlight

Here’s an experiment to try. It’s a thought experiment – it would be almost impossible to carry out in reality, though more delicate experiments roughly along these lines have been done. You’re in one of the space shuttles, or the Discovery One, or your favorite fictional but realistic spacecraft. It has a hallway extending the…

In every cop drama there’s a scene where a suspect is being questioned in an interrogation room. The room contains a large mirror, and behind that mirror the detectives and district attorneys are observing and arguing about the progress of the case. The mirror is a two-way mirror. These kinds of mirrors aren’t complicated. Light…

The Worst Physics Article Ever

Ladies and gentlemen, I give you the worst physics news article I have ever seen: Freaky Physics Proves Parallel Universes Exist Every word in the title is wrong but “physics”. It’s not freaky, doesn’t prove anything we didn’t already know, and has nothing to do with parallel universes nor does it shed any light the…

Sunday Function

Happy Easter, everyone! This Sunday Function is going to be short and sweet, since unfortunately I’ve got a lot to do before Monday. Let’s get down to business! Here’s a function I’ve made up out of thin air. It’s pretty arbitrary – in fact, it’s discontinuous at x = -1/2 and not differentiable at x…

Astrology and Gravity

There’s a classic problem in physics textbooks which asks you about astrology. It’s sometimes said – the problem will tell you – that the gravitational pull of the doctor delivering you is stronger than that of Jupiter, therefore it’s unlikely that the planets are exerting a whole lot of influence on your life. The problem…