Measurement and Uncertainty. SPH 3U1. SI Units. “SI” stands for “ Systeme International d’Unites ”. It is a system of units used in measurement. All physical quantities can be expressed as some combination of fundamental units, called base units. Unit Conversions: Prefixes.
(1 mile = 1.61km)
How close value is to accepted value
How exact and reproducible a value is
Good accuracy, poor precision
Good precision, poor accuracy
Good accuracy, good precision
State final answer with the same number of significant digits as the number with the least number of significant digits.
E.g. 26.32m ÷ 2.23 s =
50 m x 121 m =
2.10 cm ÷ 501.00 s =
How can we express each of the above to
the correct number of significant digits?
4.19 x 10-3 m/s
Number from 1 to <10, expressed to correct significant digits
Express 1233.45m3 to three figures.
Express 0.00000046667m/s to two figures.