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Physics/volumetric expansion of heated water



I wonder if you would be so kind as to help me with the following question:-

if for example ,1 liter of water was contained within a vertically orientated steel cylinder with closed bottom and a piston floating on the surface of the water making an air tight seal to the inner wall of the cylinder ( the piston is weightless and can be driven up and down the cylinder with zero frictional losses )

Immersed in the water is an electric heating element that if energized in air will have a surface temperature of 200c and the cylinder and piston are perfectly thermally insulated.

Question:- what will the volumetric increase of the water/steam be if the heating element is permanently energized ? I.E how far would the piston be driven up the cylinder if the cylinder has an infinitum length

Thank you for considering and helping me with this

Best regards


Hello Roland,

Considering the zero losses, weightless piston, permanently energized heater, etc, I would expect the temperature to rise without limit. I suppose that the steam is also to be considered an ideal gas. Therefore, considering Boyle's Law, I would expect the volume to increase without limit. So I would expect the piston to rise to infinity.

I hope this helps,


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Steve Johnson


I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.


I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University

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