Re: mechanical equivalent of heat

[Ludwik Kowalski <kowalskiL@MAIL.MONTCLAIR.EDU>]

OOPS, A TYPING ERROR WAS CORRECTED dT=0.018 degree

Ludwik Kowalski wrote:

> kyle forinash asked:
>
> > Does anyone have a simple mechanical equivalent of heat
> > laboratory exercise (1st year undergrad level)?
> >
> > I know of two; lead shot falling in a tube (which has horrible
> > accuracy) and the 'calorimeter on a crank' appratus (pretty
> > costly). I don't like either. ...
>
> Somebody who has access to a shop can produce something
> like this. It is a sealed iron tube (3 kg) and an iron piston (10 kg)
> inside, with some air. The piston can travel 1 meter from one
> end to another; it has holes allowing air to sip during a vertical
> fall. Suppose the tube, well insulated with styrofoam, has a
> mechanical release system to trigger the fall of the piston. By how
> much should the temperature increase? PE decreases by 98 J
> producing 23.4 calories of heat. Assuming all of it goes to 13
> kg of iron the expected dT is 0.018 degree (in a single shot).
> Can such dT be measured with a thermister to within ~1%
> accuracy? I do not know.
> Ludwik Kowalski