1. Measurement Systeme Internationale Changing Units Order of Magnitude pps by C Gliniewicz

2. Standards To make any measurement, one needs only to define a standard Every person could define their own units but it is more convenient for everyone to use the same standards We use the Systeme Internationale or metric system Abraham Lincoln signed the law which made the United States a metric country pps by C Gliniewicz

3. There are seven base units in SI Length is the metre Mass is the kilogram Time is the second Temperature is the Kelvin Molecular quantity is the mole Light intensity is the candela Electric current is the ampere pps by C Gliniewicz

4. Conversion factors are quantities equal to one For example, 60 seconds equals 1 minute pps by C Gliniewicz

5. Dimensional Analysis or Changing Units is the use of these quantities to cancel units until the desired result is reached For example pps by C Gliniewicz

6. The following prefixes are commonly used in physics Tera-, T, 10 12 Giga-, G, 10 9 Mega-, M, 10 6 kilo-, k, 10 3 centi-, c, 10 −2 milli-, m, 10 −3 micro-, , 10 −6 nano-, n, 10 −9 pico-, p, 10 −12 pps by C Gliniewicz

7. Order of Magnitude is used to estimate the approximate answer One estimates the size to the nearest power of ten One rounds values from the square root of ten, 3.16 (or 31.6 or 316, etc.) One can estimate the number of marbles needed to fill a classroom by saying a marble is about 1 cubic centimetre and a classroom is about 100 cm high, 1000 cm wide and 1000 cm long, giving 10 8 cubic centimetres or marbles. pps by C Gliniewicz

8. Length is defined as the metre, the distance light travels in 1/299,972,458 seconds A second is the time needed for a particular wavelength of cesium light to vibrate 9,192,631,770 times A kilogram is the mass of a platinum- iridium cylinder whose height and diameter are equal which is kept in Serves, France An atomic mass unit is 1.6605402×10 −27 kg pps by C Gliniewicz