What happens at almost 30 inches of mercury?

Ms. Vanos said people are most comfortable with barometric pressure of 30 inches of mercury (inHg). When it rises to 30.3 inHg or higher, or drops to 29.7 or lower, the risk of heart attack increases.

Is 30 inches of mercury high pressure?

Atmospheric pressure is usually measured in inches of mercury (inHg or Hg). High air pressure is considered to be greater than 31 inches or can be less than 29 inches. Normal pressure at sea level is 29.92 inches.

Is 30 inches high or low 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 tall must a column of mercury?

approximately 30 inches
At sea level and at a temperature of 0° Celsius (C), the height of the mercury column is approximately 30 inches, or 76 centimeters. This represents a pressure of approximately 14.7 psia. The 30-inch column is used as a reference standard.

How is inches of mercury measured?

In the U.S., the common standard to measure rough vacuum is inches of mercury (“Hg), which can be measured in two different ways. One method is as “Hg gauge (“HgV), where the scale starts at 0″ Hg (atmospheric pressure) and goes up to 29.92” Hg, which is perfect vacuum.

Why do we use inches of mercury?

Because liquids are much denser, if you filled that same one inch square column with water, it would only take about 34 feet to weigh the same as a 20-plus mile high column of air. So “an inch of mercury” is the pressure equivalent of about 1/30th of an atmosphere.

How does inches of mercury work?

A column of air an inch square extending out to the top of the atmosphere (over 20 miles) weighs about 14.5 pounds, and therefore exerts a pressure of 14.5 pounds per square inch (1 bar) at sea level. So “an inch of mercury” is the pressure equivalent of about 1/30th of an atmosphere.

How many inches of mercury is a perfect vacuum?

29.92″ Hg
In the U.S., the common standard to measure rough vacuum is inches of mercury (“Hg), which can be measured in two different ways. One method is as “Hg gauge (“HgV), where the scale starts at 0″ Hg (atmospheric pressure) and goes up to 29.92” Hg, which is perfect vacuum.

Does pressure get higher as you go up?

Pressure with Height: pressure decreases with increasing altitude. The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels.

Why are inches of mercury used?

Inch of mercury (inHg and ″Hg) is a unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States.

What is the height of the mercury column used for?

The height of the mercury column serves as an indicator of atmospheric pressure. At sea level and at a temperature of 0° Celsius (C), the height of the mercury column is approximately 30 inches, or 76 centimeters. This represents a pressure of approximately 14.7 psia. The 30-inch column is used as a reference standard.

What is the amount of vacuum in inches of mercury?

The amount of vacuum, in inches of mercury, is equal to the weight of the column of water from the water table to the surface. Atmospheric pressure at sea level is 29.92 inches (approx. 76 cm) of mercury. This is equivalent to a column of water 406.7 inches or 33.9 feet (approx. 10.3 m).

What are the physical characteristics of mercury?

Along with Venus, Earth, and Mars, Mercury is one of the rocky planets. It has a solid surface that is covered with craters like our Moon. It has a thin atmosphere, and it doesn’t have any moons. Mercury likes to keep things simple. Mercury spins slowly compared to Earth, so one day lasts a long time.

What happens if you touch a mercury column with CO2?

Caution: Do not touch the bulb until it has warmed sufficiently for the mercury to emerge from the bulb into the capillary. Never subject the stem or mercury column to the CO 2 solution, as it will freeze the mercury column in the capillary and may cause the bulb to fracture.