# What causes the pressure of the atmosphere?

Key idea: Atmospheric pressure is caused by the weight of the atmosphere pushing down on itself and on the surface below it. Pressure is defined as the force acting on an object divided by the area upon which the force is acting.

What is the value of atmospheric pressure?

Standard atmosphere. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101325 Pa (1.01325 bar), equivalent to 760 mmHg (torr), 29.92 inches Hg and 14.696 psi.

## Which planet has the highest atmospheric pressure at the surface?

At 92 bar (9.2 MPa), the atmospheric mass is 93 times that of Earth’s atmosphere and the pressure at the planet’s surface is about 92 times that at Earth’s surface. Venus is also the hottest planet in our Solar System, with a mean surface temperature of 735 K (462 °C/863.6 °F).

## What causes air pressure to decrease?

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.

## Where would the air pressure be the greatest?

Air pressure is the highest near the Earth’s surface where air particles are squeezed close together by the weight of the air above. Air pressure is the force with which the air presses down on things. The greater the altitude, the lower the air pressure. pressure is the greatest and the lowest.

## What causes high pressure in the atmosphere?

Areas of high and low pressure are caused by ascending and descending air. As air warms, it ascends leading to low pressure at the surface. As air cools, it descends leading to high pressure at the surface. This is illustrated in the diagram below.

## Why does a fire in a fireplace burn more briskly on a windy day?

Why does the fire in a fireplace burn more briskly on a windy day? Bernoulli’s Principle says the wind will cause a lower pressure at the top of your chimney compared with inside your house. So air rushes up your chimney. This draft feeds more oxygen to the fireplace, making the fire burn faster and hotter.

## Is atmospheric pressure higher on a mountaintop or at sea level?

Therefore, as you go up in elevation, or height, air pressure decreases. For example, if you were at the top of a high mountain, you would have less air pushing down on you than you would if you were at sea level. Both air and water are fluids. However, air is different from water because air is a gas.

## What is caused by the difference in air pressure?

Wind results from a horizontal difference in air pressure and since the sun heats different parts of the Earth differently, causing pressure differences, the Sun is the driving force for most winds. Friction (Fr) – very little effect on air high in the atmosphere, but more important closer to the ground.

## Is atmospheric pressure the same everywhere on the surface of the earth?

Atmospheric pressure is not the same everywhere on Earth. Atmospheric pressure depends on the altitude (or height) of your location. Many places on Earth are at sea level, which has an atmospheric pressure of 1 kilogram per square centimeter (14.7 pounds per square inch).

barometer

## What is atmospheric pressure in ATM?

One atmosphere (101.325 kPa or 14.7 psi) is also the pressure caused by the weight of a column of fresh water of approximately 10.3 m (33.8 ft). Thus, a diver 10.3 m underwater experiences a pressure of about 2 atmospheres (1 atm of air plus 1 atm of water).

## What is the barometric pressure of?

Barometric pressure (also known as atmospheric pressure) is the force exerted by the atmosphere at a given point. It is known as the “weight of the air”. A barometer measures barometric pressure. Measurement of barometric pressure can be expressed in millibars(mb) or in inches or millimeters of mercury (Hg).

## Why is it important to know the air pressure?

Barometric pressure has important effects on water chemistry and weather conditions. It affects the amount of gas that can dissolve in water. More gas, such as oxygen, can dissolve in water under higher pressure when compared to lower air pressure.

## How does atmospheric pressure affect the body?

Changes in barometric pressure that accompany storms and shifts in weather patterns do affect our bodies, and many people are more sensitive to those effects than others. According to biometeorologist Jennifer Vanos, Ph.D., when the barometric pressure drops, so does your blood pressure.

## Why does air pressure vary around the world?

That is, as the altitude increases, atmospheric pressure decreases. This is due to the fact that air molecules are constantly being pulled downwards (towards the center of the Earth) by Gravity. So, air molecules are tightly packed near the surface of the earth, compared to some higher altitude.

## What is the pressure of Earth’s atmosphere?

14.7 pounds per square inch

## How much pressure is exerted on the human body?

At sea level, because of the 60-mile column of atmosphere between you and outer space, there’s about 15 pounds per square inch of air pressure pushing down on every part of your body. Now go pick up a 15-pound weight.

## What is the instrument that measures air pressure?

An instrument that measures air pressure is called a barometer. One of the first barometers was developed in the 1600s. The original instrument had mercury in the small basin, with an upside down glass tube placed in the mercury.

## What is the approximate pressure of air at sea level?

14.70 pounds per square inch

## Why does the atmosphere exert pressure on the earth?

The molecules making up a gas, such as the gases in our atmosphere, are not bound to each other at all. They are free to move about, bumping into each other as well as into liquids and solids. At sea level, the amount of pressure exerted by our atmosphere is about 14.7 pounds per square inch.

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