Saturday, April 3, 2010

Building a working cloud chamber, part 2.

Today was a rather busy day for me. I and my partners in Modern Physics met again today to try and get our cloud chamber project working. It was a rather mixed session. Initially, we had high hopes, as we had corrected several of the problems that plagued our first generation attempts. However, despite doing everything right that we could think of, we were still unable to see even the faintest wisp of cloud. After repeated attempts, we were about to give up in frustration and think about finding another project altogether, when I suggested for lack of any better idea that we invert the setup to have the heat source on the bottom and the dry ice on top, to create conditions more in line with the earth's hydrological cycle. Lo and behold, almost immediately after flipping everything over and applying a slight vacuum we observed some extremely faint clouds. However, this success was tempered by the fact that the clouds were too faint to actually observe any particle tracks, even after repeated attempts fiddling with various parameters.
We finally stopped again after a while, with several more ideas for improvements and the fact that we had managed to observe something. I'm attaching a humorous picture of our setup below; let me stress that the vapor in the picture is not the cloud we saw, it's from some dry ice I put in the container to create a nice visual effect. We never saw anywhere near that much cloud from the alcohol.

It's the intrepid radiation-carrying Lego man of science!

Yes, that's our radiation source that he's carrying on his head. It fits perfectly into Lego-sized openings, so we used a Lego man to hold it up and keep us from losing it. What you actually see is just the aluminum casing, the americium is only exposed in a tiny portion on the very top.
My classmate whose apartment we were running the experiment at lives right on the beach, and I actually saw a whale breaching while I was there. It was out in the ocean a couple hundred meters offshore, just expelling a huge cloud of water vapor (a lot more cloud than we ever saw in our experiment!).

Doing my latest round of complex analysis homework today, I had some really mixed feelings. Now that I've reached this point in the semester, I know enough theorems and propositions to actually accomplish some impressive things. I'm struck by how often a really complicated looking integral can be evaluated very simply, and turn out to be quite easy in the end. It's taken two months to get to this point, two months of building the scaffolding theorem by theorem, problem by problem, with little (up to this point) to show for it, so it's nice to finally be able to really do stuff.


  1. Does this mean there will be further Cloud Chamber experiments?

  2. Oh yes. Hopefully next time we will be able to actually report a particle detection!


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