# How do you read a mercury barometer?

1. Zero the barometer at the bottom. Use the adjusting knob to carefully lower the surface of the merecury reservoir below the tip of zeroing peg.
2. Take the reading at the top. Slide the vernier above the top of the mercury column.

## What is considered high and low barometric pressure MB?

Values around 1013 mb and higher indicate an influence from a high pressure system. Strong highs will have values well above 1013 mb such as 1030 millibars. Low pressure tends to bring in cloudier, windier and stormy weather while high pressure tends to bring in less clouds, lighter wind and fair weather.

## How do you calculate barometric pressure in chemistry?

1. Convert from inches of mercury (read from the barometer) to millibars: if you know the inches of mercury, simply multiply by 34.433.
2. Convert from psi to mm of mercury: multiply the psi by 51.7.
3. Convert from psi to inches of mercury: multiply the psi measurement by 2.041.

## How does a barometer measure pressure?

A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure. The atmosphere is the layers of air wrapped around the Earth. That air has a weight and presses against everything it touches as gravity pulls it to Earth. Barometers measure this pressure.

## How does a barometer measure height?

1. Measure the height of the barometer and then stand it next to the building when the sun is about 45 degrees in the sky.
2. Drop the barometer off the top of the building, measure how long it takes to hit the ground, and use this value to calculate the height of the building.

## How do you find the atmospheric pressure on a mercury barometer?

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 are the numbers on a barometer?

The numbers on a common barometer range from about 26 to 31, with divisions of 10 or more in between each number. A needle (actually a hand similar to a clock hand) points to the numbers on the barometer and moves in response to the changing air pressure.

## Is 30.12 barometric pressure high?

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).

## Is 29.91 high barometric pressure?

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.

## Is 1024 a high pressure?

A barometric reading over 30.20 inHg is generally considered high, and high pressure is associated with clear skies and calm weather.

## What is a barometer in chemistry?

A barometer is an instrument used to measure atmospheric pressure. A traditional mercury barometer consists of an evacuated tube immersed in a container of mercury. Air molecules push down on the surface of the mercury. Because the inside of the tube is a vacuum, the mercury rises inside the tube.

## How do you use the barometric formula?

Derivation of the barometric formula at constant temperature 3 is used again for the pressure and mass density at sea level: M/RT = ρ0/p0. The value of scale height H is between 4 and 8 km depending on the temperature.

## How do you convert barometric pressure to PSI?

1 inHg = 3386.39 pascals (Pa) psi value x 6,894.76 Pa = inHg value x 3,386.39 Pa. psi value = inHg value / 2.03602.

## What does the barometer reading mean?

Simply put, barometric pressure is the measurement of air pressure in the atmosphere, specifically the measurement of the weight exerted by air molecules at a given point on Earth. Barometric pressure changes constantly and is always different depending on where the reading takes place.

## What is normal barometer reading?

Know what represents reasonable barometer readings Normal is 29.9; range ~29.6 – 30.2 inches Hg (752-767 mm Hg)… at SEA LEVEL!

## How does a barometer work step by step?

Here’s how it works: Inside of an aneroid barometer is a small flexible metal box. Since this box has had the air pumped out of it, small changes in external air pressure cause its metal to expand and contract. The expansion and contraction movements drive mechanical levers inside which move a needle.

## What unit does a barometer measure?

Weather forecasters use a special tool called a barometer to measure air pressure. Barometers measure atmospheric pressure using mercury, water or air. You’ll usually hear forecasters give measurements in either inches of mercury or in millibars (mb).

## What does high barometric pressure mean?

High barometric pressure supports sunny, clear, and favorable weather conditions, but lower levels promotes rainy and cloudy weather conditions. This atmospheric parameter has been used for hundreds of years to forecast weather conditions.

## What is the height of a barometer at atmospheric pressure?

This can be compared to the height of mercury in a mercury barometer at atmospheric pressure, which is just 2.49 feet.

## What does 30 mean on a barometer?

That means a glass tube, with its air pumped out and sealed at its upper end and placed in a dish of mercury at its lower (open) end, would have mercury pushed by air pressure up to a height of 29.92 inches in the tube. An air pressure of 30 inches means the mercury will have risen to a height of exactly 30 inches.

## What is considered a low barometric pressure?

A barometric reading below 29.80 inHg is generally considered low, and low pressure is associated with warm air and rainstorms.