What does Pressure measure?

• A. The speed of an object in a particular direction.
• B. The force applied to a unit area of surface.
• C. Degrees of something in Celsius or Fahrenheit.
• D. The capacity to do work.

Answer: (B)

Pressure measures how hard a force is pushing on a surface per unit area. It’s defined as force divided by the area over which that force is applied, and the common unit is the pascal (one newton per square meter). This means the same push spread over a tiny area creates a much higher pressure than the same push spread over a large area. That’s why a sharp nail concentrates force on a small spot and can penetrate, while a wide surface with the same force exerts less pressure. In fluids, pressure acts on surfaces in all directions and explains phenomena like air inside a tire pushing outward or the atmospheric pressure that surrounds us. The other ideas—speed (how fast something moves), temperature (how hot or cold), and the ability to do work (energy)—describe different quantities and do not measure how force is distributed over an area.