Atmospheric Pressure

Atmospheric pressure is the force exerted by the weight of the air above an object on the Earth's surface. It is also known as barometric pressure, and it is the pressure caused by the weight of the atmosphere pushing down on the Earth's surface and on objects on the surface.

Factors Affecting Atmospheric Pressure

Several factors can affect atmospheric pressure, including altitude, temperature, and weather conditions. As altitude increases, atmospheric pressure decreases. This is because there is less air above, so the weight of the air pressing down is reduced. In terms of temperature, as temperature increases, air molecules move faster and spread out, resulting in lower pressure. Conversely, as temperature decreases, air molecules move slower and come closer together, leading to higher pressure. Weather conditions such as high and low-pressure systems also affect atmospheric pressure.

Measuring Atmospheric Pressure

Atmospheric pressure is commonly measured using a barometer. A barometer can be an aneroid barometer, a mercury barometer, or an electronic barometer. It measures the pressure exerted by the atmosphere by balancing the weight of the mercury or aneroid capsule against the atmospheric pressure.

Effects of Atmospheric Pressure

Changes in atmospheric pressure can have various effects on living organisms and the environment. For example, changes in pressure can affect weather patterns and can cause shifts in wind patterns. Additionally, changes in pressure can impact human health, particularly for individuals with respiratory issues. Divers also need to consider atmospheric pressure when diving, as changes in pressure can affect their bodies.

Study Guide

1. Define atmospheric pressure and explain its causes.
2. Discuss the factors that affect atmospheric pressure.
3. Explain how atmospheric pressure is measured and the instruments used for measurement.
4. Describe the effects of atmospheric pressure on the environment and living organisms.