The size of the reservoir in a barometer

[gyshalom]

im learning that the weight of a coloum of mercury in a barometer is balanced by the air pressure working on the reservoir at the base of the mercury tube..does the surface area over which the air pressure works matter? i understand that it is the height of the coloum,not the over all mass of the liquid being balanced in the coloum that matters when it comes to pressure..does that mean that a ton of mercury can be sustained via air pressure working on a reservouir with one kilogram over all mass?

 

[pixel01]

The pressure depends only on the height no matter how big the reservoir is. One ton or any amount of mercury can be balanced by very small bulb in the other side.

 

[sir-pinski]

The size of the reservoir in a barometer is an important factor in determining the accuracy and reliability of the instrument. As you mentioned, the weight of the column of mercury is balanced by the air pressure working on the reservoir at the base of the tube. However, the surface area over which the air pressure works does matter in this equation.

A larger surface area means that the weight of the column of mercury is distributed over a larger area, resulting in a lower pressure on the reservoir. Conversely, a smaller surface area means that the weight is concentrated in a smaller area, resulting in a higher pressure on the reservoir. This is why barometers with larger reservoirs are more accurate, as they are able to distribute the weight of the column more evenly.

In terms of the overall mass of the liquid being balanced, it is the height of the column that matters, not the total mass. This means that a ton of mercury could potentially be sustained by a reservoir with a smaller overall mass, as long as the height of the column remains the same.

In conclusion, the size of the reservoir and the surface area over which the air pressure works are important factors in the accuracy and reliability of a barometer. While the overall mass of the liquid being balanced is not as significant, the height of the column is the crucial factor in determining the pressure exerted on the reservoir.