PHYSICS AND MEASUREMENT FUNDAMENTAL QUANTITIES SI units Time

PHYSICS AND MEASUREMENT

FUNDAMENTAL QUANTITIES SI units: Time – second Mass – Kilogram Length – meter

TIME Before 1967, a second was defined as (1/60)(1/24) of a mean solar day. As this is based on the rotation of Earth, it is not universal. Redefined as 9, 192, 631, 770 times the period of vibration of radiation from the cesium-133 atom making use of the high precision atomic clock.

MASS Defined by the mass of a specific platinum-iridium alloy cylinder kept at the International Bureau of Weights and Measures in France. Established in 1887 Duplicate at the National Institute of Standards and Technology in Gaithersburg, MD.

LENGTH A meter is the distance traveled by light in a vacuum during a time of 1/299, 792, 458 second. (1983) Originally defined as one ten-millionth of the distance from the equator to the North Pole along a longitudinal line that passes through Paris. (1799, earth-based) Until 1960, distance between to marks on a specific platinum-iridium bar. Between 1960 -1970, defined as 1, 650, 763. 73 wavelengths of orange-red light emitted from a krypton -86 lamp.

PERCENT ERROR Percent error is a way of comparing a calculation or a measurement to an exact, known value.

STANDARD DEVIATION

ADDING AND SUBTRACTING WITH STANDARD DEVIATION

MULTIPLYING AND DIVIDING WITH STANDARD DEVIATION

EXAMPLE CALCULATION

EXAMPLE CALCULATION CONT…