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by Balgair 3046 days ago
I remember my 2 unit physics Lab Class, barely. We did the Millikan Oil Drop as one of three of the horrendous experiments we had to preform. Jesus.

The experiment, in brief, is to irradiate tiny oil drops and then tune a pair of charged plates until you can get one oil drop to levitate. Since electrons are unitary in charge, you can then back calculate the charge of the electron based on the charge you put on the plates.

The set up is that you have a microscope, an oil atomizer to make the drops, the charged plates, and a small radioactive source to put electrons on the oil drops. Spritz, open the lead chamber, irradiate, look at the drops in the microscope, tune the charge, repeat.

Numerous problems emerged:

Myself and my partner were pretty blind without our glasses, which you have to take off to use the microscope. So we could see nothing. (found this out on the first day, fuuuuun)

The oil drops, when imaged, are about the same size as your retina cells, in the given microscope. This means you can never be sure that you have an oil drop or your eyes are just too noisy to see it. (found this out by the end of the first week)

The room must be perfectly dark to see the oil drops in dim light, also you must take data on a computer or by writing somehow. (found this out on the first day too)

The small bit of radioactive material was made radioactive in 1961. Given the halflife of the sample, my banana was more radioactive (found this out in 2 weeks)

The plates weren't connected to anything. (2 weeks wasted)

The oil atomizer was meant for baby oil, not vegetable oil, as was given to us and wasn't actually atomizing anything. (another weeks wasted)

The end result was, well, nothing.

We got nothing. Not for lack of trying. I think I slept about 2 hours a night that whole quarter, the rest of the time was spent in the lab and on HW for other classes. My partner and I discovered that if you put your thumb over the co-ax of a high voltage, low current powersource it would zap you something fierce and keep you awake through the early morning hours. I also discovered that taking 2 ibuprofen per Rockstar will lessen the jitters of the caffeine enough so that you can read your own writing later on. So that's nice, I guess.

Stay in CS kids. Physics is for idiots.

1 comments

> Myself and my partner were pretty blind without our glasses, which you have to take off to use the microscope. So we could see nothing.

Intuitively, this doesn't make sense to me. Microscopes have a focus. You should be able to adjust that focus such that the microscope is also correcting your vision, just like I (very nearsighted) have no trouble using binoculars without wearing my glasses.

What am I missing?

Honestly, you are right, but it was nearly a decade ago now. We should have seen something.

We should have done a lot of things better, actually.

Maybe we really didn't have a microscope? The apparatus was built in ~1961 and had been used yearly for the next 50 years. Any semblance of a manual had long since disappeared. Perhaps a lens or two had been raided in the 1980's ans we couldn't figure that out in the soup of other problems. I've really no idea, a decade on, which of the problems we were having that was our 'show-stopper'.

All I know is that Advanced Physics Lab (2 units) continued the time honored tradition of the Physics major breaking you, and then kicking you while you were down and laughing at your idiocy, for 4 years straight.

Somehow, I miss those times...