Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] gravitational force



Follow up -- back in 1955 the Cavendish expt. was a frosh lab. at CIT.

bc

Bernard Cleyet wrote:

I semi-disagree w/ John.

It just takes patience. Once it's levelled and aligned *, the data is easily analysed by video taping the LASER's spot and using a player that steps frames. There is at least one commercial Michell balance that has a digital output goniometer, but I think that's cheating.

OTOH, if one wants to "really" cheat use the servo-balance one devised by R. E. Crandall, which won an AAPT apparatus competition.

AJP (51) April '83 pp. 367 ff.

Once set up, data is recovered and the value of G found in 20' -- It's especially suited for demonstration.

* Leybold's

bc, who thinks video taping is as far as he's gone and will go, AND knows JD's sarcasm.

p.s. Sci. Am's Amateur Scientist has at least two "instructions" for amateur construction of Michell balances.
p.p.s. Mike doesn't have a Behr Free Fall apparatus? Similarly as one poster pointed out (manual plotting), I think analysis of wax tapes is, in this silicon age, still very instructive.

John Denker wrote:


On 10/31/2006 12:13 PM, Mike VanAntwerp wrote:




Sure- thanks for the sarcasm.

1) No sarcasm was intended.

2) I don't even understand what /seemed/ sarcastic. If you think
"please ask a more specific question" is sarcastic, you should see
what happens when I *intend* to be sarcastic.




I'm looking for ways to get students to
work with Kepler's Laws and F= G (m1m2/d^2) in a lab setting. This is
for a high school class.


It can't be done. You can work with F = m g (i.e. small g)
but not "F= G (m1m2/d^2) in a lab setting" (i.e. big G).

The problem is that G is too small. A Cavendish balance is more
suited to grad school (or perhaps upper-division undergrad school)
than to high school.

_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l





_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l