Thursday, April 19, 2007


Or, The Hobby That's Trying to Take Over

With my help, of course.
So, a month or so ago, I got Mike into geocaching. Now he's hooked, and even has a cache by the school. A new listing for Inner Space came up, so I HAD to go get it. Nick and Brian were heading out to do some errands, so I decided to tag along, since we all were going in the same general direction. We got to talking about various forms of seizure disorder that Brian might have along the way, and before you know, we were there. Searched for a bit, and then Brian says, "Hey, guys..." and holds up a peanut butter jar full of cool stuff... with a sprinkler system vent cap on top. He then lets out a whoop, and we sign the log and trade.
Yes, a sprinkler system vent cap. It was in the ground in a section of PVC pipe. I can't make this stuff up!
Nick says he's going to be an evil cache placer now... and I, for one, believe him!

Wednesday, February 21, 2007

Thursday, February 15, 2007

On Art

Or, A New Header for the Blog

As you may have noticed, we now have a nice title image on this blog. This is thanks to my good friend Erica Henderson, an illustrator-for-hire of magnificent skill, cunning, and guile. Now everyone say, "Thank you, Erica!"

Wednesday, February 14, 2007

On Fuses and Their Uses

Or, Zappy Zappy, Joy Joy

I believe it was having a Fluke meter that did it.
Honestly, nothing is more of a magnet for damage than an expensive piece of equipment, and multimeters are far from a counterexample to this theorem.
Back when I was in my freshman year at NJIT, I was friends with a fellow named Garrett. Somehow we'd kind of glommed together a research group of sorts, and also gotten ourselves a lab to play with.
Now it happened that, at this time, a certain 3kV power supply happened to meet with an atmospheric pressure Helium plasma chamber that we'd devised. Fun was had, and to check our threshold voltage, we used the lab tech's Fluke multimeter.
Boy, but that was a mistake.
I was manually turning down the feed volume of Helium, letting the small leak around one of the electrodes do the work of producing a smooth resistance gradient over time, when the periodic sparks from anode to cathode got less and less frequent... and then stopped.
Now, normally this would be a good thing, but we still heard the sparks discharging, and they were getting faster.
Then I look at the multimeter, and the pulsing bright light coming from behind the plastic face plate.
"Garrett!" I say, "Shut it down!"
He shuts down the power supply, and, without thinking to wait for the bleeder resistors to discharge the supply's huge capacitors, I grab the jack going into the multimeter and pull hard.
Or at least, I was going to.
A spark leaps from my left pinky knuckle to the metal chassis of the power supply, a quarter of an inch away. My other hand clutches harder on the banana plug, with its semi-exposed contacts.
The power supply had been at 3kV at 10mA. My approximation is that I got about 1.5kV at about 1-2mA.
Lesson here: the orchestra has it easy; it's the conductor who has it hard.
Oh, and as for the Fluke meter, well, expensive equipment usually has the advantage that it's well designed. We only had to replace a fuse in it for it to work again perfectly with no lasting damage. Our diagnosis was that one spark ionized the static air in the meter case, allowing for the spark to effectively create a continuous arc, shorting out the multimeter. Two bits of soldering, and it was fixed.

Tuesday, February 13, 2007

A De Lorean for the Physics Majors

Or, Evan's Foray into the Arts

We were all in G118/G120, the classroom where we have Electrodynamics, early one monday. About a half of an hour early.
Now, note well the fact that a large amount of Physics majors in one place at one time allows for more mayhem.
A perfect illustration of this postulate was the fact that we got to speaking about "Back to the Future".
Then Evan said that he wanted to draw a De Lorean on the board.
His first attempt, by his own admission, was, at best, pathetic.
"Wait a moment..." I said. I went over to the computer, brought up a picture, and turned on the projector (which points directly at the whiteboard). We went to work.
About thirty minutes later, Dr. Anderson walks in, himself late, and says, "That's beautiful! The only problem is... now I can't use that half of the board. I can't erase something that great!"
It was only then that Mike brought up the point that there were actually three De Loreans for the three movies.
I noted that we'd only drawn a generic De Lorean, and not the Time Machine De Lorean.
Evan groaned.

Squamous and Rugose

Or, What Statistical Physics Really Is

To quote the great Samuel Langhorn Clemens, "There are three kinds of lies: lies, damn lies, and statistics."
That's the problem with statistical physics. It's a system that's totally artificially generated to give you certain predictable results out of the chaos of reality.
This explains why, in the middle of Dr. Buna's Mathematical Methods in Physics class, I pulled out my pocket notebook and wrote in it, "This isn't Physics; it's the third kind of lie."
And showed it to Nick.
Who glared at me and made gestures meaning to pay attention to Dr. Buna.
Some people have no sense of humor.

Monday, February 12, 2007

On Potentiometers

Or, Why Nick Was Once Called Cheech

One day, during the Fall 2005 semester, Nick and Keith were working on a project in Dr. Anderson's Analog Electronics class. Nick has never had that much luck with discrete analog components, and this day was no exception. In fact, I'd smelled just a few fried LEDs from all over the room, but across the bench from me, they were cooking up the greatest batch that day. Nick hooked up a potentiometer, supposedly to delimit the potential on one of these very LEDs. Apparently the power supply didn't like him that day, for as I watched in horror and disbelief, the back of it lit up red, and burst into flames. Mind you, Nick was still holding the control stub of the potentiometer at this point, so I shouted, "Nick!" and shut down the power supply. He's all like, "What'd you do that for?" and goes to touch the potentiometer. "No!" I say. "It was just on fire!" "Oh."
Dr. Anderson is attracted by the fuss. "What's the matter, Nick?"
"Well, I just smoked the pot."
Somewhere, a pin dropped.
Everyone looked at each other in complete and utter silence, and then, exactly four seconds later, burst out laughing simultaneously.
"Good job, Cheech!" I declared, to redoubling laughter.