Building a Cloud Chamber (Cosmic Ray Detector)

I first read about making one's own cloud chamber as a kid. I used to read old issues of Scientific American for the Mathematical Games columns written by Martin Gardner, which I highly recommend, and the Amature Scientist column written by a series of authors over the years, starting in 1928.

The projects were amazing. My favorites to read about were the seismographs and telescopes. Several cloud chambers were described, the first in September of 1952. These were of varying complexity, some made from peanut butter jars, etc.

I believe that these columns are still in print in various forms (collections published in books and on the internet as reprints from Sci. American). Not all of the project could be undertaken lightly. Particle accelerators, x-ray machines are two risky ones that come to mind.

The diagrams that accompanied the columns were notable for their clarity and ability to illustrate.

These are really easy and fun to put together. I'd highly recommend it for a weekend project.

Here's one that I built running with a sample of Americium 241 from a cheap smoke detector: http://bit.ly/UDWpc0

Here's a different one running with a bit of Thorium containing lantern mantle http://bit.ly/1Annrp5

You can also try with thorated tungsten welding rods and other household sources of radiation.

I came across this article while researching whether Coleman lantern mantles are still radioactive. Putting a mantle close to this detector would be one way to find out. Traditionally, lantern mantles were made with Thorium to produce a brighter and whiter light.

It turns out that most current mantles (including those made by Coleman) have switched in the 1990's to using non-radioactive Ytterbium, although some claim that that the older Thorium mantles are both safe and more effective: http://www.colemancollectorsforum.com/post/peerless-mantles-...

If you are excited by this but don't have a good source of dry ice (and are electronically inclined) there is an interesting alternative design that uses Peltier coolers and a PC power supply instead: http://www.instructables.com/id/Make-a-Cloud-Chamber-using-P...

Thanks, an amazingly beautiful demonstration which seems not very wide known. Here is the video from "Harvard Natural Sciences Lecture Demonstrations" which is quite beautiful (just the thing at work, without distractions) http://www.youtube.com/watch?v=e3fi6uyyrEs

I did this as a kid - serious fun. Used the americium from a smoke detector as a source, after several abortive attempts to build a synchrotron... The third time you wind several km of copper just to end up melting it is the last time, it turns out - particularly after you explain to your parents what exactly it is you're trying to do.

Either way, a small radioactive source is just great for some neat photos and the occasional decay trace.

Leftovers from my melty mess went into a tesla coil, so not all was lost.

Very pretty. I built a (less pretty) digital version a few years ago[0], based on some really neat projects by this guy[1]

[0]: http://kapamaki.net/muon-detector/ [1]: http://www.hardhack.org.au/

I saw this for the first time in a Brian Cox show:

http://youtu.be/fWxfliNAI3U

His suggestion that cosmic rays might have driven evolution is mind blowing!

Youtube has a bunch of nice videos of cloud chambers. Here's a good one: http://www.youtube.com/watch?v=SnKvtazt5So

Saw my first one while visit Bridge at Caltech.. inspired me to build my own

I saw a cloud chamber in operation at a German university, very impressive.