On Fri, Jan 9, 2009 at 10:19 AM, Andy Greener <[email protected]> wrote: > Hmm, kinetic energy -> heat - this gets better! So the area of clear > water below the lock has a relationship to the potential energy > 'stored' in the pound above and the leakiness of the gates :-)
Remember that the ice is just on the surface where the cold air can get at it. The average temp of a section of a canal is actually much above freezing, and so stirring of the water through either boats, or drops in level, or through flow will reduce the ice. Where the flow is great enough, i.e. rivers and narrow sections, it may take much lower temps to create ice. Other structures around the canal, bridges, high walls (i.e. lock walls), and even trees can increase the air temp and reduce the air flow thus reducing ice formation. Heat created by conversion from kinetic energy would be quite small on the scales we are talking about I would guess. I'm sure a scientist will be along soon with more thermodynamics :-) Cheers, Mike -- Michael Askin http://shoestring_DOT_zapto_DOT_org/
