1. Time
1.1. SI Unit
1.1.1. Second
1.1.1.1. Defnition
1.1.1.1.1. 9192631700 times the period of oscillation of radiation from the cesium atom
1.2. Instrument used for measurement
1.2.1. Digital stopwatch
1.2.1.1. Precise to 0.01 seconds
1.2.2. Sundials
1.2.3. Atomic clock
2. Length
2.1. SI Unit
2.1.1. Metre
2.1.1.1. Definition
2.1.1.1.1. Length of path travelled by light in a vacuum during during a time interval of 1/299792458 of a second
2.2. Instrument used for measurement
2.2.1. Vernier Caliper
2.2.1.1. Precise to 0.01cm
2.2.2. Micrometer screw gauge
2.2.2.1. Precise to 0.001cm
2.2.3. Metre rule
2.2.3.1. Precise to 0.1cm
3. Mass
3.1. SI Unit
3.1.1. KIlograms
3.1.1.1. Definition
3.1.1.1.1. mass of a certain cylindrical piece of platinum-iridium alloy kept at the International Bureau of Weights and Measures at Sevres, France
3.2. Instrument used for measurement
3.2.1. Electronic Balance
3.2.1.1. Precise to 0.1 g
3.2.2. Beam Balance
3.2.3. Sliding Balance