The course venue got moved from buckingham (30 min away) to Wednover (1 hour 15 min away) which made for a proper adventure.
We left work at 3 - to give us plenty of time to get there and we managed to arrive in good time for some pints and crisps- we wanted proper food but it turns out that wendover is a backwards place and no-where sells food till after 5pm. which was when our course started.
The drive was really funny- its been ages sinceI've driven a car full of people- I'd forgotten how interesting and distracting it can make journeys!
We made a cloud champer each and got them working just using cosmic radiaton- although you can use welding rods as a radioactive source.
We also tried bananas. they just froze solid.
After the course we tried another pub for food- they didn't serve any but we had some more pints and chatted about terry pratchett.
so, it is now almost 10pm on a weeknight and I've finally got in my front door- and I am the proud owner of a very home made looking cloud chamber...
it turned out that making a cloud chamber isn't very taxing- here are the instructions from the royal society of chemistrys website:
A clear, see-through box-like plastic container, with flat sides and an open top, roughly 20 x 30cm (open side) x 15cm (height)
• A metal plate (at least 5mm thick) to cover the open size of the container completely (plate must be a little bit larger than the box). The plate should be preferably black and should have a little grooves matching the side walls of the plastic box. As this is probably hard to find, you can also use a flat metal plate and use black electrical tape to make the metal plate surface black.
• A thick felt (few mm), a bit smaller than the bottom of the box. • 4 clips (self-adhesive cable-tie holders + cable ties) to attach the
felt to the inside of the bottom of the box • A small wooden box that is just a little bit larger in area than the
metal plate and approx. 5cm in height. The box later on has to take the ice plates and the metal plate but the sides should not be much higher so that it doesn’t cover the plastic box.
• A very intense, bundled light source, e.g. a slide projector, strong flashlight ...
• Pure (not 70%) isopropyl alcohol – make sure you get the right one – it will only work well with this one it and keep it out of reach of children).
• Dry Ice (Careful with your hands – always use thick gloves and never touch the ice directly! The ice is at -78oC; touching it directly will give you a burn.)
• Security goggles to handle the ice • Gloves to handle the ice and the alcohol
A Cloud Chamber, is a device used by nuclear physicists to detect and study elementary particles Among the many particles that can be detected are alpha particles, protons, electrons, positrons, and various types of mesons. These particles are emitted by unstable (radioactive) atomic nuclei and produced during nuclear collisions. Some of them reach the earth as cosmic rays.
In a cloud chamber, the path of a particle appears as a track of mist called a cloud track. By studying the track, or a photograph of it, a physicist can determine the energy and electric charge of the particle that produced it. Every kind of particle has a characteristic cloud track, which varies in shape, length, and width. Many elementary particles have been discovered through their characteristic cloud track.
Don't get too excited- its basically an upside down fish tank of alcohol, mounted on a baking tray, placed in a gratinal tray of dry ice.
I'll post some photos soon
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