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Re: [Phys-l] Schlieren photography in high school laboratory

No, but I run a simple setup every year in my Applied Optics course. I use a mirror that I happen to have kicking around that is similar to a small telescope mirror. My mirror is about 6 inches in diameter with a focal length of about 1 meter. The setup is very easy, some years I'll have a particularly motivated student that will take pictures through the pinhole. Lining the camera up and getting it to focus at the right spot is the only tricky part.

I use a very bright LED a few cm back from a pinhole (about 2 mm in diameter). I mount the pinhole about s = 2f from the mirror and then use the mirror to image that pinhole onto a second identical pinhole. Both pinholes are drilled in a sheet of galvanized steel similar to what HVAC ducts are made with. When you look through it the image is so bright that we usually have to turn the LED brightness down. It makes for a pretty sensitive system. You can play with the position of the second, "viewing," pinhole to get either bright or dark field. Both are interesting.

All you need is a mirror and something to hold the mirror, two similar "pinholes" and mounts and a light source and you are good to go. I use a couple of ring stands to hold the pinholes. Very primitive setup but very sensitive.

For about $50 you can get a B/W security camera that is a pinhole camera. You might be able to use that as the second pinhole. There are no focus issues with a pinhole camera and you can get video output. I've not tried this, but I'm curious now... :-)

All the best,

John


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
John E. Sohl, Ph.D.
Professor of Physics
Weber State University
2508 University Circle
Ogden, UT 84408-2508

voice: (801) 626-7907, fax: (801) 626-7445
cell: (801) 476-0589
e-mail: jsohl@weber.edu


"Alby Reid" <alby@bleary-id.co.uk> 11/15/2008 10:35 AM >>>
Has anyone tried carrying out Schlieren photography (or even videography) in
a high-school-level-equipped laboratory? Any tales of success or woe?


Alby

--
Alby <alby@bleary-id.co.uk>