The SI unit for pressure is the Pascal (Pa), named after the French mathematician Blaise Pascal. Pressure can be understood as the force exerted by gas molecules on the walls of their container. In a gas, molecules move randomly in straight lines, colliding with each other and the container's surfaces. This random motion leads to the concept of pressure.
To quantify pressure, we use the formula:
\( P = \frac{F}{A} \)
where \( P \) represents pressure in Pascals, \( F \) is the force in newtons (N), and \( A \) is the area in square meters (m²). This relationship highlights that pressure is the force applied by gas molecules distributed over a specific area.
Understanding pressure is crucial as it lays the groundwork for exploring more complex concepts such as ideal gases, which follow specific laws under certain conditions, and non-ideal gases, which exhibit behaviors that deviate from these laws due to interactions between molecules.