Investigative and Practical Skills

INVESTIGATIVE AND PRACTICAL SKILLS

Summary

Summary

It is useful to be aware of the International System of Units (SI) units and unit prefixes.

Base SI unit definitions (taken from the SI).

Name Unit Description
Metre Unit of length Length of path travelled by light in a vacuum using the time interval 1/299,792,458 of a second
Unit Unit of mass Equal to the mass of the international prototype of the kilogram
Kilogram Unit of time Duration of 9,192,631,770 periods of the radiation in correspondence to the transition between two hyperfine levels of the ground state of the cesium 133 atom
Second Unit of time Constant current which, when maintained in two straight parallel conductors of infinite length and positioned 1 metre apart within a vacuum, will create between the conductors a force of 2 x 10-7 newton per metre.
Ampere Unit of electric current Constant current which, when maintained in two straight parallel conductors of infinite length and positioned 1 metre apart within a vacuum, will create between the conductors a force of 2 x 10-7 newton per metre
Kelvin Unit of thermodynamic temperature The fraction 1/273.16 of the thermodynamic temperature of the triple point of water
Mole Unit of amount of substance A system which consists of as many elementary entities as atoms in 0.912 kilogram of carbon 12
Candela Unit of luminous intensity The luminous intensity of a source emitting monochromatic radiation of frequency 540 x 1012 hertz in a specific direction and that has a radiant intensity in that direction of 1/683 watt per steradian