# Atmospheric Pressure

Earth’s atmosphere is a relatively thin collection of gases. These gases are essential to life on Earth. As you move further from the Earth’s surface, the density and the atmospheric pressure both decrease.

The less dense the air is, the lower the air pressure will be. In contrast, the denser the air, the higher the pressure. This pressure can change with altitude.

The density of gas particles is highest closer to the Earth’s surface, with pressure decreasing as you ascend. This means:

• At higher altitudes, the air pressure is lower
• At lower altitudes, the air pressure is higher

Therefore, an object at sea level experiences a higher atmospheric pressure than one on top of a mountain. At sea level, more particles surround the object, leading to more collisions and as a result, a greater force on the object. If there are more collisions then there will be a greater force acting on the object.

By looking at the pressure equation:

We can see that, as long as the area remains constant, increasing the force leads to an increase in pressure. This is why the higher force acting on the object at sea level leads to an increase in pressure.

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