Metric and Measurement Notes

Seven Basic Measurement Areas (Metric Units)

Length The basic unit of measurement for length is a: meter. The instrument used is a: meter stick. Standard: distance light travels in 1/2.9979x108 seconds or 3.3x10-9 seconds

Mass The basic unit of measurement for mass is a: gram. The instrument used is a: triple beam balance. Standard: plantinum iridium cylinder – stored in a vault in the International Bureau of Weights and Measurements in France

Mass vs Weight Mass – amount of particles (atoms) a substance contains Weight – force of gravity pulling on an object

Time The basic unit of measurement for time is a: second. The instrument used is a: stopwatch Standard: 9x109 vibrations of Cesium 133

Temperature The basic unit of measurement for temperature is: Celsius (or Kelvin). 0°C (freezing) . . . . . . . . . . . . . 100°C (boiling) The instrument used is a: thermometer. Standard: the triple point of water – the temperature and pressure at which solid, liquid and vapor are all present = 273.16K or 0.01C

Amount of a Substance The basic unit of measurement for the amount of a substance is: a mole Avogadro’s number: 6.022x1023 Standard: the amount of substance containing the same number of particles as 12.00g of carbon 12

Light Intensity The basic unit of measurement for light intensity is: candela (cd) The instrument used is a: spectrophotometer Original definition: the amount of light emitted by a common candle. Standard: intensity of a source that emits a monochromatic light of 540x1012Hz with an intensity of 1/683 steradians

Electrical Current The basic unit of measurement for electrical current is: Ampere (A) The instrument used is an: amp meter Standard: the amount of electrical charge passing a point in an electrical circuit per unit time with 6.241x1018 electrons OR a force of 2x10-7N/m between 2 parallel conductors of infinite length of negligible cross section in a vacuum

Derived Units Units that are formed by any combination of basic units: Area (l x w) Volume (l x w x h) Density (m/v) Force (N = kgm/s2)

Volume The basic unit of measurement for volume is a: liter. The instrument used is a: graduated cylinder. Measure the volume of liquid at the bottom of the meniscus. NEVER use a beaker for measuring volume, it is not accurate.

Volume (cont.) To measure the volume of a regularly shaped solid, multiply: length x width x height Basic unit of volume for a solid: m3

Density (cont.) Equation: mass/volume Basic unit of measurement of density: Solid: g/m3 Liquid: g/L

Metric System The metric system is based on the number 10 and multiples of 10. kilo hecta deca basic deci centi milli k h dk d c m 1000 100 10 1 0.1 0.01 0.001 or or or 1/10 1/100 1/1000

Additional Metric Prefixes Tera 1012 Giga 109 Mega 106 Kilo 103 centi 10-2 mili 10-3 micro (μ) 10-6 nano (n) 10-9

Approximations and Conversions 1 m ≈ 1 yard 1 in = 2.540 cm 1 L ≈ 1 quart 1 qt = .9463 L 1Kg ≈ 2 lb 1 lb = 453.6g 1 mile = 1.609 Km