Pressure

Syllabus tag: KCSE | Physics | Form 1 | Topic 4 Pressure

Lesson objectives

By the end of this topic, you should be able to:

• Define pressure and state its SI unit.
• Calculate pressure in solids and in liquids.
• Explain atmospheric pressure and describe instruments measuring it.
• State and apply Pascal's principle, including the hydraulic press.

Summary

Pressure is force per unit area, measured in pascals (Pa), where 1 Pa = 1 N/m². In a liquid, pressure depends only on depth, density and gravity — never on the shape or width of the container. Atmospheric pressure is about 10⁵ Pa at sea level, and Pascal's principle states that pressure applied to an enclosed fluid is transmitted equally throughout.