On approximations

Approximations are cool. Really. I'm gaining a whole new appreciation for them this semester. For one thing, I'm in my first ever 'engineering' class, and really, all of engineering is based on approximating. Approximate a woodpecker as a mass spring system (no, seriously, see this link. In particular, check out the diagram on page 5). Approximate a spring as linear. Approximate, approximate, approximate.
Or take my theoretical mechanics class. We find crazy systems of differential equations and then approximate to solve them. Or solve them numerically, which involves approximating every step of the way (no pun intended).
Anyhow, the reason I was inspired to post after all this time was a combination of two quotes. The first:
"How fast is this rocket going? Just a general guess."
"Erm ... very fast."
"No, I want one sig. fig., not zero!"

And the second:
"It turns out 4 is a really lousy approximation for pi"

I will admit to being the speaker for the second quote. I was trying to create a wire binding for a small handmade book, and needed this coiled wire to be a circle with a given radius. Not being one for measuring sticks, I needed to figure out how long I needed to coil the wire before tying off. Since I wanted a circle of at least that given radius, I figured I'd round pi up a bit, but ... well, as the quote says, 4 is a pretty lousy approximation for pi.

Ah, the adventures of life.

:-)

Fun things

I know I haven't posted in a while; I apologize.
I just wanted to share a couple of fun things going on right now.
First off, for the first time, I have unicycled wearing a skirt (and shorts underneath, but that's not the point!). The scariest thing is the dismount, because if my skirt catches on the seat, it sends either me or the unicycle into the ground.
Second, experimental archaeology is a legitimate field. Enough said.

Successful use of the Meta key

In case I haven't mentioned it before, I'm an emacs person. Well, I finally found how to use something other than the escape key as emacs' Meta key. The Meta key is another command key, like Command on the Mac keyboard or Control on Macs or PCs. On Windows machines, the Alt key is automatically used as the Meta key, but for some reason, the Alt/Option key on the Mac isn't set to Meta in emacs. It's bothered me for about as long as I've had my computer. However, today I finally figured out how to fix it! It has to do with not emacs but Terminal, the command-line interface in Mac OS-X.
In Terminal, go to Terminal > Preferences > Settings > Keyboard and check the 'Use Option as Meta key' checkbox.
Hooray!

Thanks to this website for describing the solution!