Perception of lake surface (?)

Merrymeeting · 11-29-2011, 06:27 PM

It does make you wonder...

This is the first year in many that I've been able to spend a significant amount of time at the lake at this time of year. It does seem that the water is significantly calmer most of the time.

I assume it is a combination of several factors. Number 1 is probably the lack of boat and human activity on the water. I'm sure that CLA could give us a weather analysis that shows that the winds are either calmer or different (or both) at this time of year. And I do wonder if the increasing density of the water due to temperature has anything to do with it.

What I can say is that the lake is beautiful any time of year. This morning when I got up, the water was dead calm, mirroring the mountains and shoreline above, mist hovered over the low lands and valleys, and the sunrise was adding a pink, blue, purple hue to the whole scene. It was beautiful... and unfortunately I didn't have my camera.

Jonas Pilot · 11-29-2011, 06:47 PM

... what I said before. If you have a "critical eye" and spend a lot of time on the water, and are out when the ice breaks in the spring and don't put your boat away until the launch is too slippery to launch, you can see a difference in the waters apparent viscosity.

SIKSUKR · 12-01-2011, 09:19 AM

And corrected.Water density changes much more than I thought with reguard to temperature.First,liquid water is not most dense at 39.2.On the chart I link here it clearly shows a higher density right up to the freezing point.At 70 degrees it has a viscosity of 1 and at 39 degrees it is about a 1.55.Quite more significant than I realized.

http://www.engineeringtoolbox.com/wa...ity-d_596.html

DickR · 12-01-2011, 11:18 AM

SIK, that link shows only dynamic and kinematic viscosity. Searching on that site gives this:

http://www.engineeringtoolbox.com/wa...ght-d_595.html

The temperatures are every 10 degrees, but the table does show a maximum in density at "around" 40 F. A better source, such as the ASTM steam tables, gives the density at temperatures more closely spaced.

Water is a strange chemical in many ways, relative to other types of compounds. Density is one strange property, having a maximum somewhat above its freezing point, but that is why deep lakes can freeze over, while the heavier water, above the freezing point, settles down toward the bottom. And of course the density of water gets lower still upon freezing to the solid state, allowing it to float on the surface and not sink.

11-29-2011, 06:47 PM	#2
Jonas Pilot Senior Member Join Date: Apr 2005 Location: Wolfeboro, New Hampshire is my home, 24-7-365 Posts: 1,686 Thanks: 1,047 Thanked 336 Times in 189 Posts	I stand by ... ... what I said before. If you have a "critical eye" and spend a lot of time on the water, and are out when the ice breaks in the spring and don't put your boat away until the launch is too slippery to launch, you can see a difference in the waters apparent viscosity.

12-01-2011, 09:19 AM	#3
SIKSUKR Senior Member Join Date: Apr 2004 Posts: 5,075 Thanks: 215 Thanked 903 Times in 509 Posts	I stand aside.. And corrected.Water density changes much more than I thought with reguard to temperature.First,liquid water is not most dense at 39.2.On the chart I link here it clearly shows a higher density right up to the freezing point.At 70 degrees it has a viscosity of 1 and at 39 degrees it is about a 1.55.Quite more significant than I realized. http://www.engineeringtoolbox.com/wa...ity-d_596.html __________________ SIKSUKR

11-29-2011, 06:27 PM	#1
Merrymeeting Senior Member Join Date: Mar 2003 Location: Merrymeeting Lake, New Durham Posts: 2,226 Thanks: 302 Thanked 800 Times in 368 Posts	It does make you wonder... This is the first year in many that I've been able to spend a significant amount of time at the lake at this time of year. It does seem that the water is significantly calmer most of the time. I assume it is a combination of several factors. Number 1 is probably the lack of boat and human activity on the water. I'm sure that CLA could give us a weather analysis that shows that the winds are either calmer or different (or both) at this time of year. And I do wonder if the increasing density of the water due to temperature has anything to do with it. What I can say is that the lake is beautiful any time of year. This morning when I got up, the water was dead calm, mirroring the mountains and shoreline above, mist hovered over the low lands and valleys, and the sunrise was adding a pink, blue, purple hue to the whole scene. It was beautiful... and unfortunately I didn't have my camera.

12-01-2011, 11:18 AM	#4
DickR Senior Member Join Date: Apr 2008 Location: Moultonborough Posts: 751 Thanks: 4 Thanked 259 Times in 171 Posts	SIK, that link shows only dynamic and kinematic viscosity. Searching on that site gives this: http://www.engineeringtoolbox.com/wa...ght-d_595.html The temperatures are every 10 degrees, but the table does show a maximum in density at "around" 40 F. A better source, such as the ASTM steam tables, gives the density at temperatures more closely spaced. Water is a strange chemical in many ways, relative to other types of compounds. Density is one strange property, having a maximum somewhat above its freezing point, but that is why deep lakes can freeze over, while the heavier water, above the freezing point, settles down toward the bottom. And of course the density of water gets lower still upon freezing to the solid state, allowing it to float on the surface and not sink.

The Following 2 Users Say Thank You to DickR For This Useful Post:
Jonas Pilot (12-01-2011), SIKSUKR (12-02-2011)