Redefining SI units

Learning Outcomes: H2: 1(a), 1(b)

Curriculum Emphasis: Nature of Science, Science, Technology, Society and the Environment

How are measurement standards established?

Explore how the SI units are defined, and use the opportunity to discuss the impact of the 2019 redefinition of the SI units in their lives. Students can also explore the importance of establishing an international or national measurement system, such as the National Measurement System overseen by the National Metrology Centre (NMC) in Singapore.

Education and Career Guidance: Teachers might also showcase interesting related jobs, e.g. metrologist, quality engineers, etc.

Resources: 

• SLS Lesson – Physical Quantities and SI Units

• A-Star National Measurement System: Metrology standards

1.  Measurement must depend on rules called standards. Things are measured based on comparison to standards 2.The SI was made to establish an international standard, applicable anywhere. It is based on seven based units, the set on which all other SI units are derived from. 3. Physics depends on measurements, and measurements depend on standards. Measurements and standards are in place to establish consistency and accuracy, and to aid communication and comparison. Units are the standards chosen to represent quantities. Units can be derived from other units and converted into other ones.