What is Pressure? Basic Concepts
Pressure is simply the amount of force pushing on a certain area. Imagine pushing your finger on a balloon – the harder you push (force) or the smaller the area of your finger, the more pressure you create. In chemistry and physics, pressure is often related to how gas particles hit the walls of their container.
- Force per Area: The fundamental definition of pressure.
- Standard Pressure: A common reference point, often defined as 1 atmosphere (atm) or 101.325 kilopascals (kPa).
- Gauge vs. Absolute Pressure: Gauge pressure is measured relative to the surrounding air, while absolute pressure is measured relative to a perfect vacuum (no pressure at all).
- Atmospheric Pressure: The pressure exerted by the weight of the air above us. It changes with altitude and weather.
- Unit Relationships: Different units exist because of historical reasons and specific applications (e.g., mmHg for blood pressure, psi for tires).