Standards of measurement What is a standard? A standard is an exact quantity that people agree to use to compare measurements

Units of mesurements What is missing in the below picture? The length of the string ball is 150 For any measurement to make sense, it must include a number and a unit

Systems of units People in the world uses two systems of units: English system Metric system Foot Inch Mile Gallon Pound Minute second Meter Centimeter Kilometer Liter Kilogram Minute second

In the SI there are seven base units for seven base quantities Scientists around the world uses a unified system of units called the SI (International System of Units). In the SI there are seven base units for seven base quantities Quantity Measured Unit Symbol Length meter m Mass kilogram Kg Time second s Electric current ampere A Temperature Kelvin K Amount of Substance mole mol Intensity of Light Candela cd

SI is an easy system because it is based on multiples of 10. Prefixes with units are used to convert to multiples and parts of the units. Prefix Symbol Multiplying Factor Giga- G- 1000 000 000 Mega- M- 1000000 Kilo- k- 1000 Deci- d- 0.1 Centi- c- 0.01 Milli- m- 0.001 Micro- µ- 0.000 001 Nano- n- 0.000 000 001

Divide () multiply (×) Converting units using prefixes Giga (G) 1000 Mega (M) (Unit) meter(m) gram(g) Liter(L) Second (s) 1000 kilo (k) 1000 10 deci (d) 10 centi (c) 10 multiply (×) milli (m) 1000 micro () 1000 nano (n)

Examples on converting units using prefixes 1- 3 mm = _________ m 0.003 3  10  10  10 3  1000 0.003 2- 5.4 Kg = _________ g 5400 5.4 × 1000 5400 3- 20 g = _________ g 0.00002 20  1000  10  10  10 20  1000000 0.00002

Examples on converting units using prefixes 4- 3 m = _________ cm 300 3 × 10 × 10 3 × 100 300 5- 370 g = _________ kg 0.37 370  1000 0.37 6- 36 g = ___________ ng 36000000000 36 × 10 × 10 × 10 × 1000 × 1000 36 × 1000000000 36000000000

Examples on converting units using prefixes 7- 150 mL = _________ L 0.15 150  10  10  10 150  1000 0.15 8- 1.4 L = _________ mL 1400 1.4 × 10 × 10 × 10 1.4 × 1000 1400 9- 8 s = ___________ s 8000000 8 × 10 × 10 × 10 × 1000 8 × 1000000 8000000

Examples on converting units using prefixes 10- 0.3 Mm = _________ m 300 000 0.3 × 1000 × 1000 0.3 × 1000 000 300 000 11- 2000 kg = _________ Gg 0.002 2000  1000  1000 2000  1000 000 0.002

Quiz 2 Thursday 06/10/2011 Chapter1 – Section 2 Standards of measurement