Measurements and Units

Contents / notes

• Fundamental units: length, mass, time, electric charge, temperature, luminous intensity and amount of substance.
• Derived units: weight, area, volume, force and speed.
• Measuring instruments: vernier calipers, metre rule, micrometer screw gauge, measuring cylinder, stopwatch and beam balance.
• Fundamental physical quantities.
• Derived physical quantities and their units.
• Combinations of fundamental quantities and determination of their units.
• Dimensions: definition and simple examples.
• Limitations of experimental measurements: accuracy of measuring instruments, estimation of errors, significant figures and standard form.

Candidate objectives

• Identify the units of length, area and volume.
• Use different measuring instruments.
• Determine the lengths, surface areas and volumes of regular and irregular bodies.
• Identify the unit of mass.
• Use simple beam balances, such as Buchart's balance and chemical balance.
• Identify the unit of time.
• Use different time-measuring devices.
• Relate fundamental physical quantities to their units.
• Deduce the units of derived physical quantities.
• Determine the dimensions of physical quantities.
• Use dimensions to determine the units of physical quantities.
• Test the homogeneity of an equation.
• Determine the accuracy of measuring instruments.
• Estimate simple errors.
• Express measurements in standard form.