What is the action of a mercury barometer?
Mercury barometers are primarily used for measuring atmospheric pressure. It is a device that consists of an upside-down tube filled with mercury that is in a vessel full of mercury. The atmosphere (or the air) pushes down on the mercury in the vessel, which in turn, pushes the mercury in the tube up.
Who invented mercury?
Mercury or quicksilver has been known since ancient times. We do not know who discovered it. Mercury was known to the ancient Chinese, Egyptians and Hindus and has been found in Egyptian tombs dating back to about 1500 B.C.
How is a mercury barometer constructed?
The basic construction, unchanged since Torricelli’s experiment in 1643, is a glass tube about three feet long, closed at one end, filled with mercury, and inverted with the open end immersed in a cistern of mercury. …
What is the working principle of barometer?
A barometer is essentially a balance. The weight of the atmosphere is balanced by the weight of a much shorter mercury column. You can’t use an ordinary pan balance to weight the atmosphere (because air is pushing down on both sides).
What is barometer and its uses?
A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure. Changes in the atmosphere, including changes in air pressure, affect the weather. Meteorologists use barometers to predict short-term changes in the weather.
How does a mercury barometer work physics?
A barometer can be made by filling up a long glass tube with mercury, then turning it upside down in a bath of mercury as shown. The space at the top of the barometer tube is a vacuum and exerts no pressure on the mercury column. The vertical height of the mercury column gives the required atmospheric pressure.
What is gas pressure exactly?
Gas pressure is caused by the force exerted by gas molecules colliding with the surfaces of objects (Figure 1). Although the force of each collision is very small, any surface of appreciable area experiences a large number of collisions in a short time, which can result in a high pressure.