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Re: [Phys-L] Bourdon tube foundations

On 10/26/2012 10:56 AM, Roberto Carabajal wrote:
Please, I would appreciate a link to a detailed description of the Bourdon
tube gauge pressure operation, because in general what I have founded show
the final formula but not the foundations including Hooke`s and Young`s
Thanks for your time.
My best regards.
Forum for Physics Educators

Perhaps, depending on the age of the target audience, an explanation could be offered which provides more toehold for the intellect?
I visualize a concertina walled tube, restrained along one lengthwise surface strip with a tape. If this device is inflated, it will curl towards the tape. There is no great difficulty here.

If we make such a tube in a curve, we may fix a flexible tape to either the exterior ridges at the perimeter, or at the most minor perimeter. It will be evident that a structure of this kind can be made to uncurl, or to curl, when inflated.

It's true that this leaves the educator with a remaining bridge to cross: how to explain the necessity of an elliptical cross section, if we would avoid a pleated arrangement?

Perhaps one could argue from the geometry: for circular arcs bound together by structure an action which necessitates their distance increasing but their length remaining the same is resolved by an increased radius for both?

Brian W