Re: [Phys-L] really using a barometer to measure heights at a construction site

[bernard cleyet <bernardcleyet@redshift.com>]

First:  

Geologists use(d) an extremely high resolution aneroid barometer.  I had an aviation one with 10 foot labeled dial resolution.  It was spot on (once I’d calibrated w/ the first sign) on my way to skying at Clair Tappan (Sierra Club at Donner pass).  

The twin tube suggests a method to thermally correct for the density variation.  

The crude method to supply quickly hot water from a central heater is a circulator.  Using the second tube, pump, a temp. sensor, and a software correction, will do it, no?  

bc,  …    has a single pipe hot water supply upstairs.  It’s a pump at the tank that forces the hot thru a check valve (upstairs bath) into the cold pipe.  Has a timer, so energy (thermal and electric) is “conserved”.  

> On 2018/Jul/29, at 11:59, John Denker via Phys-l <phys-l@mail.phys-l.org> wrote:
>
> The word "isothermal" is doing a lot of work in that
> statement.
>
> An interesting homework exercise might go like this:
>  Estimate the systematic error incurred in the following
>  situation:  The cord is draped over a 10m high wall.
>  The true elevation difference (between the base unit
>  and the readout) is essentially zero.  Because one
>  side of the wall is facing the hot sun and the other
>  side is in the shade, there is a 10 °C temperature
>  difference between the upgoing and downgoing parts
>  of the cord.




> On 2018/Jul/29, at 13:46, John Denker via Phys-l <phys-l@mail.phys-l.org <mailto:phys-l@mail.phys-l.org>> wrote:
>
>
> The basic ziplevel "cord" is AFAICT just a tube.
> The patent holds out the possibility of a twin tube
> but I don't think they implemented that in any models
> I'm aware of.