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Re: projectors



Tanks!

that's what I suspected, however, I think a hi-quality monitor with S-video might
be "acceptable."

It went, like, now I know why I'm not a H.S. teacher. The decay curve was distinct
once, at Jeff's suggestion, I connected the dots, but not much else, as you know.
I had intended to have two groups of three or four do a dice simulation. I have
about 700 -- one group would do a third (pick out all the 1, 2, and 3's) and the
other just the ones. Then plot for the class. I managed to do on the board
1/6(100); 1/6(100-1/6<100>); etc. But the bell rang before we could plot it. I
asked them to do it as home work -- wonder how many will. I also managed to
qualitatively show the absorption of beta's with Al (Tl-204), the absorption of
beta's then gamma's with Al then Pb (Cs-137), and the stopping power of a sheet of
onion skin paper for alphas (Am-241 from a smoke detector -- illegal!), also the
activity of K (KCl) and my radium dial watch, but forgot the fiesta ware, a sheet
of mica, and my French lantern mantles.

bc

Jeff found it very interesting that Cs is not so dangerous as one would think,
because it has a biological half life of < a year. (~ 70d, and, if in gut,.
reduced to v. ~ 20d with prussian blue)



John Gastineau wrote:

-----Original Message-----

Speaking of resolution, I just returned from doing a radioac. decay
demo. for my
friend's Chem. class at N. High. I used his large TV, my new G4
portable, and Vernier's
rad. monitor, Logger Pro and Lab. Pro. interface -- the resolution was
worse than
unacceptable!

Did I do something wrong, or should the HS get a projection system, or
for less, a
hundred dollar camera, and have it look at my G4 screen?.



The resolution of a typical TV (used with an Elmo type device or with a
computer-to-video adapter) is far less than the resolution of a computer monitor
or a computer data projector. There's no comparison at all. Text on a computer
screen, unless it is very large, is illegible when shown on a TV.

If you want the class to be able to see what you see on a computer screen, you
need a proper computer data projector. Even a 640x480 pixel projector is far
better than a TV of any quality.

How did the demo go?

JEG

--
John E. Gastineau john@gastineau.org
140 Tenderfoot Road (301) 387-8494
Oakland MD 21550-6957 (301) 387-8495 fax
USA http://gastineau.org