Date: Wed, 29 Nov 2006 21:12:24 GMT From: th <someguynospamwhere.se> Subject: Re: Terrible Screaming Noise
Greg Farris wrote: > In article <456DBBD4.90707nospamwhere.se>, someguynospamwhere.se says... > >> There is one other exception: Water expands when cooled below 4 degrees >> C. > > > This is true - though not the only known negative temperature expansion > coefficient. > > >> Due to this effect lakes freeze at the surface and we can go skating! > > > > Due to which effect? Wouldn't that be more closely related to the fact that > water becomes a solid at 0°C? > You are partly right, it's a combination of two effects: 1) if the solid wouldn't have expanded but become more dense than the water the ice would sink. 2) if the 0°C water would be the most dense it would also sink to the bottom of the lake and the entire lake water must reach 0°C before ice formation can start. Then just very shallow lakes would freeze during winter. -- th