> Hmm... could make for a neat toy. Think a balance beam, one side a 
> solid
> weight, the other side my evacuated and hermetically sealed 
> cylinder.
> Eventually they won't balance...
>
> Good enough for a canada council for the arts grant application I 
> think!

Hang two similar containers on balance beam.
Place on in sunlight.
Expanding container displaces more air and loses "weight".
Beam moves.

You could use it to move a sun shield between containers to promote 
oscillation.
Over centre or similar "snap" action needed to stop it assuming an 
equilibrium stable position.
Without the shield it's a solar tracker  - see other thread :-)

I'm sure similar engines have already been built.

A significant level of power conversion may be possible if expanding 
metal was used with suitable heating and cooling applied. Someone made 
a "Sterling" (not Stirling) engine using this basic principle.



        Russell 

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