The Equivalence Principle

Ah, equivalence. A property that our lives revolve around. Yet, some people don't appreciate the relativity of equivalence, possibly because they don't understand how it works.

First, think of an elevator in space. Even though this is not physically possible, pretend that the elevator is free of all gravitational forces. There are two people in this elevator. Without any gravity, these two unlucky people are floating freely. Now, let's bring the elevator up to the free fall rate, or the speed required to emulate the effect of Earth's gravity (9.8 meters per square second, I believe). Next, pretend that the observers still believe they're on Earth (not remotely possible, hopefully). Will they know the difference between gravity and acceleration? Most likely not, as in this case acceleration has simulated gravity.

For the next example, let's take that elevator and the two brave astronauts and place them in the Willis Tower (Sears Tower, whatever). Now, we'll drop the elevator into a free fall. Not counting air resistance, the elevator should fall at a constant rate of approximately 9.8 meters per square second, as mentioned before. What will happen to the people inside the elevator? In this case, acceleration has cancelled gravity out as it is going toward gravity's pull.

Finally, picture the same elevator one last time, but instead of two travelers there is a beam of light stretching across the elevator in a perfectly horizontal line. Now, we'll raise the elevator one last time. The beam of light will appear to arc downward to an observer due to the motion of the elevator, even though its path actually remains undisturbed.

This theory usually is updated to use a rocket ship, but you know me. I'm old fashioned.

Credit: Leonard Susskind's Black Hole Wars. An excellent, highly recommended book!

An Analysis of Stupid

I think that there's some sort of mental disease affecting the sophomores in my classes. When you tend to breeze through classes like I do, then you get placed in the integrated ones quite often. Unfortunately, instead of being a third wheel to them with all my geeky, glavin glory, it seems to be the other way around. And don't worry, I'll include something scientific to make it count.

Now, just last week, I was doing my homework in my intervention. Now, I'm the picture of a geek: long, messy brown tresses, dark blue eyes hidden behind thick brown wireframe glasses, extremely tall and quite flabby with a tendency to stutter. So obviously the sophomores in my classes have picked me out as their foil. I have below the transcript of a conversation with them. Be astounded at their pernicious natures!

Me: *humming and working on trigonometry*
"T": Hey, Rebecca.
Me: Salutations.
"T": *stares and rolls his eyes* Listen, my friend "J" is havin' some trouble with his homework. Can you help him?
J: Yeah!
Me: I have my own homework. I need to keep my grade up at 107%, you know.
T: Yeah, but J is, like, failing. He needs help.
Me (Believing him but wondering where the study tables are): I'll see what I can accomplish. What do you have here?
J: Dunno.
Me (genuinely dumbfounded): Inequalities? We learned those in the seventh grade! They're as simple as pi!
T: Hey! He's older than you! Respect your elders!
Me (taking papers with reserve): Yes, but you'll never become an engineer if you don't learn your inequalities!
J: What does drivin' a train have to do with math?
Me (OMG jawdrop): Here. Let me help you with the first few dozen...

Now, what could possibly make those boys that vapid? Beyond me. But somehow, analyzing their brains, I suspect that their hippocampus (memory center) has been affected from too many blows during football practice. Also, their rampaging hormones may be affecting their trains of thought (I'll admit even my mind strays occasionally!).

Then again, we only differ from chimps by about 1.6%. Maybe these boys are "throwbacks", and share a bit more DNA than normal with our prehensile cousins.