Measurement: Key Terms (Form 4 SPM Physics)

Terms and definitions

• Physical quantity, A quantity that can be measured, consisting of a numerical value and a unit.
• Base quantity, A physical quantity that cannot be defined in terms of other physical quantities; the five in physics are length, mass, time, electric current and temperature.
• Derived quantity, A physical quantity obtained by combining base quantities through multiplication or division, such as speed or density.
• Scalar quantity, A physical quantity that has magnitude only, with no direction, such as distance, speed and mass.
• Vector quantity, A physical quantity that has both magnitude and direction, such as displacement, velocity and force.
• SI unit, The internationally agreed system of units for physical quantities, based on the seven SI base units such as the metre, kilogram and second.
• Prefix, A word or symbol placed before a unit to indicate a multiple or fraction of it, such as kilo- (10³) or milli- (10⁻³).
• Significant figures, The digits in a measurement that carry meaningful information about its precision.
• Measurement error, The difference between a measured value and the true value of a quantity.
• Precision, The ability of an instrument to give consistent, closely grouped readings when a measurement is repeated.
• Accuracy, How close a measured value is to the true or accepted value of a quantity.
• Sensitivity, The ability of an instrument to detect and respond to a small change in the quantity being measured.
• Inertia, The tendency of an object to resist any change to its state of rest or uniform motion. (related term from another chapter)
• Mass, The amount of matter in an object; a scalar quantity measured in kilograms (kg), and a measure of its inertia. (related term from another chapter)
• Momentum, The product of the mass and velocity of an object; a vector quantity (momentum = mass × velocity), measured in kg m s⁻¹. (related term from another chapter)

Content standards these terms come from

• 1.1 Physical Quantities
• 1.2 Scientific Investigation

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 Measurement resources

• Chapter overview: Measurement
• Revision Notes
• Common Mistakes
• Practice Questions
• Paper 2 Answering Guide
• Paper 3 Guide

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