Atmospheric pressure is the weight of the air above us pressing down on the Earth's surface. It is caused by the force of gravity pulling air molecules toward the ground. This pressure is greatest at sea level, where the air is denser, and decreases as you go higher in altitude, like when climbing a mountain. This pressure affects many aspects of our daily lives, including weather patterns and how we breathe. For example, weather systems are influenced by changes in atmospheric pressure, which can lead to storms or clear skies. Understanding atmospheric pressure helps us predict these changes and stay safe.