Ask an Explainer

Static pressure is the pressure due to the random motion of the air molecules while dynamic pressure is the pressure due to the directed motion of the molecules. Since air is a gas, air molecules are constantly moving. It is easiest to understand if you imagine a steam of air in motion. If you were to move at the same speed as the flow of air, the pressure felt would be the static pressure - the random motion of the molecules as they press against you. If you were to stop this flow, you would feel the random motion of the molecules plus the directed motion of the molecules as you stopped their movement. This is called the total pressure, or stagnation pressure, which is static pressure plus dynamic pressure. When you're just standing in a room, the air has no directed motion, therefore you are only feeling the static pressure.