What pressure does a barometer read?

A barometric reading in the range of 29.80 and 30.20 inHg can be considered normal, and normal pressure is associated with steady weather. If the reading falls between 29.80 and 30.20 inHg (100914.4–102268.9 Pa or 1022.689–1009.144 mb): Rising or steady pressure means present conditions will continue.

What is the barometric pressure normal?

14.7 pounds per square inch
Average barometric pressure at sea-level is commonly cited as 14.7 pounds per square inch (PSI). However, this figure is just an average. In reality, barometric pressure varies across the world, especially at higher elevations where atmospheric pressure is much lower than at sea level.

What is the standard pressure for a mercury barometer?

about 14.7 pounds per square inch
Atmospheric pressure at sea level is about 14.7 pounds per square inch, equivalent to 30 inches (760 millimetres) of mercury, 1,013.2 millibars, or 101,320 pascals.

Is 29 high for barometric pressure?

The weight of the atmosphere on the surface of the mercury exerts a pressure transmitted through the fluid, forcing it to rise. The greater the weight, the higher the rise. The barometric pressure seldom goes above 31 inches or drops below 29 inches. Normal sea-level pressure is 29.92 inches.

What is barometer diagram?

Simple barometer – diagram An inverted glass tube is standing in the bath of mercury and air pressure is exerted on the surface of mercury. The pressure at the top of the mercury column is zero as there is a vacuum there. The height raised in glass tube is equivalent to the atmospheric pressure.

What happens to a barometer when air pressure decreases?

Barometers are used to predict the weather. A barometer measures air pressure: A “rising” barometer indicates increasing air pressure; a “falling” barometer indicates decreasing air pressure. Therefore, on any given day you would expect the air over a desert to have a lower pressure than the air over an ice cap.

How do you calculate air pressure from a barometer?

If the pressure is given in millimeters of mercury (mmHg), the barometric formula is written in the form: P(h)=760exp(−0.00012h)[mmHg]. P(h)=29.92exp(−0.0000366h)[inHg].

Is 30 high barometric pressure?

A barometer reading of 30 inches (Hg) is considered normal. Strong high pressure could register as high as 30.70 inches, whereas low pressure associated with a hurricane can dip below 27.30 inches (Hurricane Andrew had a measured surface pressure of 27.23 just before its landfall in Miami Dade County).

How does the Fortin barometer measure atmospheric pressure?

Fortin barometer. The mercury barometer’s design gives rise to the expression of atmospheric pressure in inches or millimeters or feet (torr): the pressure is quoted as the level of the mercury’s height in the vertical column.

How can you use a barometer to predict weather?

A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface troughs, high pressure systems and frontal boundaries.

Which is the best barometric pressure for fishing?

However, knowing the best barometric pressure for fishing is something you absolutely cannot overlook. When you’re considering the best times of day to fish, barometric pressure is one of those daily and seasonal fluctuations that will play a huge role in how many fish you catch – if any.

Who was the first person to invent the barometer?

Although Evangelista Torricelli is universally credited with inventing the barometer in 1643, historical documentation also suggests Gasparo Berti, an Italian mathematician and astronomer, unintentionally built a water barometer sometime between 1640 and 1643.