Pressure: Key Terms (Form 5 SPM Physics)

Terms and definitions

• Pressure, The force acting normally (perpendicularly) on unit area of a surface (pressure = force ÷ area); measured in pascals (Pa).
• Pressure in liquids, The pressure at a point in a liquid, which increases with depth and density (pressure = height × density × gravitational field strength) and acts equally in all directions.
• Atmospheric pressure, The pressure exerted by the weight of the column of air in the atmosphere on the Earth's surface and on objects in it.
• Gas pressure, The pressure produced by the collisions of gas particles with the walls of their container.
• Pascal's principle, Pressure applied to an enclosed fluid is transmitted equally and undiminished throughout the fluid in all directions.
• Hydraulic system, A system that uses Pascal's principle to multiply force by transmitting pressure through an enclosed liquid, as in a hydraulic jack.
• Archimedes' principle, An object wholly or partly immersed in a fluid experiences an upward buoyant force equal to the weight of the fluid it displaces.
• Buoyant force, The upward force exerted by a fluid on an object immersed in it.
• Principle of flotation, A floating object displaces a weight of fluid equal to its own weight.
• Bernoulli's principle, For a flowing fluid, where the speed is higher the pressure is lower, and where the speed is lower the pressure is higher.
• Manometer, A U-shaped tube containing liquid used to measure the pressure of a gas by comparing liquid levels in its two arms.
• Elasticity, The property of a material that allows it to return to its original shape and size after the force deforming it is removed. (related term from another chapter)
• Hooke's law, Within the elastic limit, the extension of a spring is directly proportional to the force applied to it. (related term from another chapter)
• Spring constant, The force needed to produce unit extension in a spring, a measure of its stiffness; measured in newtons per metre (N m⁻¹). (related term from another chapter)
• Elastic limit, The maximum force or extension beyond which a spring or material no longer returns to its original length. (related term from another chapter)

Content standards these terms come from

• 2.1 Pressure in Liquids
• 2.2 Atmospheric Pressure
• 2.3 Gas Pressure
• 2.4 Pascal's Principle
• 2.5 Archimedes' Principle
• 2.6 Bernoulli's Principle

How to learn them

1. Cover the definition, say it aloud, then check the unit.
2. Pair each term with a formula or experiment from the chapter.
3. Write the Malay term alongside the English one, SPM papers are bilingual.

More Pressure resources

• Chapter overview: Pressure
• Revision Notes
• Common Mistakes
• Practice Questions
• Paper 2 Answering Guide
• Paper 3 Guide
• Calculation practice sets

Source: DSKP KSSM Physics Form 4 and 5 (Versi English), Sijil Pelajaran Malaysia: Format Pentaksiran mulai 2021, Fizik (4531) (Bahagian Pembangunan Kurikulum (BPK), KPM)