Wednesday, May 5, 2010

Particles, magnets, and clothes, oh boy!

Wow! Today has been fantastically incredible for me. I'm going to have to troll my vocabulary for superlatives to fully describe my day.

Today, in case I haven't mentioned it before, is the day everyone in my Modern Physics class demonstrated their projects.  We were a little unsure about ours -- as I reported a few days ago, our attempt to run it on Friday, with every confidence that it would work, came to nothing, leaving us forlorn and distraught. However, Mike, my partner and the one with the actual equipment, ran it again on Saturday and was able to see many trails (humorously, he tried calling several people to tell them about it, including me, and they all for one reason or another didn't answer, leaving another classmate to quip "Mike discovered the secret of the universe, and nobody picked up the phone!"). So when we ran it today, we were hopeful about seeing trails. At first, it seemed our attempts would be in vain, as there was little alcohol rain and nary a trail in sight. However, after we'd seen everybody's projects and the class was over, Mike twiddled with it a bit, added some alcohol and set the base plate directly on the dry ice, and voila! Trails galore! I could hardly believe my eyes, at first -- 8 unsuccessful tries before seeing anything more than a random cosmic ray, and now, trails popping off in quick succession, even showering about en masse like sparklers at times. It was definitely one of the cooler and more dramatic things I've seen in my life.
I attempted to capture it on camera, but unfortunately the conditions necessary to see the trails made it very difficult to get a good picture of them. And still pictures can never do it justice, anyway. Nothing can compare to actually seeing subatomic particles interacting with the alcohol-vapor rich air in front of you, suddenly appearing and shooting along like a meteor, leaving a trail of droplets behind them to disperse and fall out of the air over a second or two. Or bouncing off the plastic aquarium containing them and ricocheting back into the chamber. I attach one of the better pictures I managed to take below. The trail in this picture is quite clearly visible as the white horizontal streak near the middle of the picture. The dark disk to the left is the uranium-doped sample, and the americium is just visible in the back corner as the tiny grey disk.

The intrepid Lego men, of course, are there to monitor and watch the proceedings.

All in all, it was amazing. Mike and I sat and watched it for almost half an hour, mesmerized by the interplay of fundamental forces going on in the chamber before us. The most fantastic part for me was seeing a trail split. That's right, I saw a single trail, straight as an arrow, suddenly spawn a second trail branching off at about a 30 degree angle. I'm positive it wasn't two trails that happened to be near each other, because the second trail quite clearly started at the first one, which kept on its straight course afterwards. What was it? I don't know. A decay seems unlikely, as uranium and americium both decay mostly to quite stable alpha particles (helium nuclei). I suspect, taking conservation of momentum into account, that it may have been an alpha particle knocking an electron loose off an air molecule causing said electron to go careening away.

The sub-atomic dance going on before our eyes was so beautiful, we found it a hard thing to finally have to take it down. There's a chance Mike will take it up tomorrow to Mauna Kea, where he'd have a good chance of being able to observe cosmic rays, and even the showers of secondary particles they create when they strike a molecule in the atmosphere, slamming into it at appreciable fractions of the speed of light.

I am happy to be able to say that I have finally been able to watch where atomic and subatomic particles go with my own eyes. While that was certainly intellectually satisfying, the second big attraction of my day -- magnets -- was incredible on a much more visceral level.

You see, one of the other project this morning required the use of a powerful magnet in order to split the spectral lines in a mercury vapor lamp. They were using a large cylindrical magnet -- and when I say large, I mean it had an interior diameter easily big enough for me to put my hand all the way through its 8-inch length without touching the insides. Our teacher, Dr. Takamiya, also brought along a small pair of extremely -- and I mean extremely -- powerful magnets. I only succeeded in separating them after putting one of them up against a corner of a desk and shoving laterally with all my strength against the other one. But while their strength was of an order unknown to me in magnets before, that in itself was not too incredible. I've played with strong magnets before. What was incredible, and completely blew my mind, was what happened when I moved them near the large cylindrical magnet.

I didn't have much in mind when I first got the impulse to hold the small magnets close to the large one (at this point they were bonded strongly together in my hand, generating a powerful field). I had a natural, subconscious hypothesis that I would simply feel a very powerful force pulling my hand towards the magnet. But that's not what happened -- not at all. I was snapped out of my assumptions about the behavior of magnets when the pair in my hand started to twist and turn, as if with a mind of their own. My memories of the event are lurid. I'm almost positive that I felt no actual force on the magnets, only torque. They weren't being attracted to the magnet so much as they were trying to align themselves with it field. Intrigued, I moved my hand up and down outside the magnets, and felt the magnets in my grip react as if alive, writhing about in an attempt to obey the commands of the invisible magnetic field they were being pulled through. It was surreal. I'm fairly certain I stood there with a huge grin lighting up my face for ten or twenty seconds, just feeling the thrill of magnets calling to each other across space. My astonished exclamations of delight and wonder quickly brought several other classmates to my side, so I relinquished the magnets to let them experience the wonder, while still myself able to feel their strange tugging in my hand. The memory still brings a thrill to my spine. Why could not we have done this in my Electromagnetism class this semester, at least once? A whole semester's worth of dry theorems and boring formulae was distilled into one intense, gripping, and powerful moment for me. If I had gotten to do this in January, I would have been excited to learn more about this mysterious force. As it is, I'm still excited from this morning, and jumping up and down inside at the remembrance.

Later, as people were preparing to leave, I got another chance with the magnets, so I took the cylindrical magnet and laid it on its side, then held a single small magnet in my hand and pushed it through the middle of the cylinder. I did feel a force this time, though again, it was drowned out by the overwhelming torque. Each time as I moved the magnet in and out of the cylinder, it desperately tried to flip itself around in order to line up with the field, then slowly tried to draw my hand towards the middle of the cylinder once it was inside. The whole experience was...beyond my meager ability to describe. You can only truly understand if you have felt the small metallic cylinders in your hand jerking and tumbling about with a life of their own to follow the unseen lines of force emanating from their larger cousin nearby. Truly, I must see about getting me some magnets of this caliber.

The third item on my list is nowhere near as exciting as the first two, but I needed a third noun for my title, and it warrants a mention. With summer coming on ( I can tell it's getting light a little bit earlier each week), and some of my older pairs of shorts showing their age, I finally found time today to run to Walmart and pick up two more pairs of my favoritest shorts. I know I know, not as exciting as watching bits of atoms flying about, or experiencing forces I turn out to have a surprising ignorance of, but it makes me happy none the less, and makes a fitting end for one of the most exciting days for me in quite a while. I need to finish this and get to bed  now, so perhaps tomorrow I'll tell you about the Residue Theorem, and how that's impacted my life. And about my upcoming observing run at the Institute for Astronomy on Thursday and Friday nights with Dr. Takamiya.
Till then, aloha!

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