bagmaker wrote:

We see a bubble in the water beside us as we rise in our scuba gear.
The bubble has eddies below it, turbulence beside and below it. It has
a smooth, rounded top and a flat bottom. This is true, however,it is
not rising by itself, as all seem to think, it is being displaced by
the water.
Thermals are no different or they would break Waynes Rule.

Really? A couple days ago, I saw a dust devil that took dust up 2000
feet in a narrow, spinning column. It didn't look anything like bubble.

The same day, a field fire created a narrow column of smoke topped by a
cloud, but it didn't spin like the dust devil. It didn't look like a
bubble, either.

I suggest that a discussion focusing on a bubble model of thermals is
doomed from the beginning, and to narrow that focus to whether it rises
because it's lighter than the surrounding air or the surrounding air is
heavier than the bubble will yield even less understanding thermals.

But, perhaps I misunderstand the goal of the proposal.

--
Eric Greenwell - Washington State, USA
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