As you might know, the Earth is covered with a blanket of gases. That is called the atmosphere. The air from the atmosphere takes up space, so it has mass (weight). The more atmosphere above you, the more the air pressure. There is actually 14.7 pounds per square inch of your body pushing down on you right now!! That means that your whole body is having about 7 tons of air pushing down on you! You can’t really feel the air pressure because your body is pushing outward, the opposite direction of the air pressure. That is what air pressure is! High pressure systems mean that a lot of air is pushing down on a certain area. High pressure systems happen when air from the center of the system sinks down towards the ground. This pushes away clouds and provides us with sunny weather. Then, there are low pressure systems. Low pressure systems form when air rises from the ground to the center of the system. As this happens, the water vapor from the ground condenses and turns into clouds. This causes cloudy and sometimes stormy weather.
