[net.physics] helpful lab hints.

CSvax:Physics:piner (11/17/82)

   It occurs to me that we are overlooking a valuable resource
here on the net. Much of what we physics pholks do is in the
lab, and in those labs are pieces of equipment. Some of them
work, and some of them don't. I think it would be helpful to
many of us, if lab experiences were passed on from time to 
time. In other words, I would like to propose that we let
others on the net know, when we encounter something which
could be useful to others in the lab, especially if it is
something unexpected. If this gets to be an popular idea,
we can always start a sub group.
  I will be glad to start off, with my own helpful hint.
If have found that the sodium arc lamp made by Gates, is NOT
useful as a spectral source. The yellow sodium doublet is
split into four lines. This is because the pressure in the
lamp is too high, and sodium is self-reversing. These lamps
are sold by Fisher and Cenco, and should not be used in
interferometer experiments. Order a spectral lamp from
someone like Oriel for this task. Indeed, always use spectral
lamps for experiments involving measurement of a spectra.
If someone had told my predecessor this, I wouldn't now have to
spend a couple of kilo-bucks to replace the lamps in my class.
   I will post other helpful hints from time to time as they come
up. If anyone else has such hints, I for one, would like to hear
them.
					Richard Piner
					Physics Dept.
					Purdue University
					West Lafayette, IN  47907