1. Standards of Measurement Chapter 1 Section 2

2. Units and Standards Standard-an exact quantity that is agreed upon to use for comparison hands feet piece of string

3. Measurement Systems English inch pound ounce Metric centimeter gram liter

4. Fundamental Units There are 7 fundamental units. All other units are a combination of these units. kilogram meter second kelvin candela mole ampere

5. Derived Units A unit that is a combination of fundamental units Newton-measurement of force combination of kg, m, and s-kg. m/s 2 Joule-measurement of energy combination of kg, m, and s-kg. m 2 /s 2

6. International System of Units SI – 1960 renamed the metric system to SI to indicate an improved version standard system of measurement used worldwide prefixes based on powers of 10

7. SI Prefixes Kilo-k-1000 Centi-c-0.01 Milli-m-0.001 Convert 23 km to mm Convert 75 g to kg

8. Measuring Distance Length (distance) l (d) distance between points units of meter, centimeter, or kilometer Appropriate use of units

9. Meter, m 1 st defined at 1/10,000,000 the distance from north pole to equator pass through Lyons, France 1983 light traveling in a vacuum for 1/299,792,458 s

10. Measuring Matter Mass amount of matter in an object units are kilogram

11. Kilogram, kg Mass of small platinum-iridium metal cylinder Not reproducible with natural occurrence

12. Measuring Time Time interval between two events unit is second

13. Second, s First defined as 1/86,400 of a solar day Universe is expanding and Earth’s rotation is slowing down so time was not constant 1960’s atomic clocks developed Now so many vibrations of Cs-133 atom

14. Measuring Temperature Temperature the measure of the hotness or coldness units are Celsius or Kelvin

15. Kelvin, K Originally Cesius based on the boiling and freezing points of water Now based on the triple point of water. Triple point is when all three phases of water are present