SOME DAY, WE’LL BE TRADING OUR FEET FOR METERS. THE METRIC SYSTEM SOME DAY, WE’LL BE TRADING OUR FEET FOR METERS.

THE METRIC SYSTEM IS BASED ON THREE DEFINED UNITS. m the meter for length kg the kilogram for mass s the second for time ALL THE OTHER UNITS ARE DERIVED FROM THESE THREE. BY COMPARISON: 1 m = 1.094 yard 1 kg = 2.205 lb 1 s = 1 s

WE CAN COMBIND THE KILOGRAM, THE METER, AND THE SECOND TO MAKE MORE UNITS. AREA = LENGTH X LENGTH = m x m = m2 VOLUME = L X L X L = m x m x m = m3 1 m3 = 1,000 liters The liter is the unit we will use for volume. 1 liter = 1.05669 quarts = 1.06 quarts

THE ORIGINAL METRIC SYSTEM WAS STARTED IN FRANCE IN 1670. THE SYSTEM, AS WE KNOW IT, WAS PUT IN PLACE IN 1960, AND IS KNOWN AS THE INTERNATIONAL SYSTEM OF MEASUREMENT, OR "Système International” IN FRENCH OR SI.

THE MORE COMMON PREFIXES Symbol Magnitude Multiplier giga- G 109 1 000 000 000 mega- M 106 1 000 000 kilo- k 103 1000 hecto- h 102 100 deka- da 10 - deci- d 10-1 0.1 centi- c 10-2 0.01 milli- m 10-3 0.001 micro- µ (mu) 10-6 0.000 001 nano- n 10-9 0.000 000 001 pico- p 10-12 0.000 000 000 001 THE MORE COMMON PREFIXES

OUR MORE COMMON UNITS OF MEASURE: MASS: gram, g 454 grams = 1 lb 1 kilogram, kg = 1000 g 1 milligram = 0.001 g VOLUME: liter, l 1 l = 1.06 quarts 1 milliliter, ml = 0.001 l LENGTH: meter, m 1 meter = 1.09 yard 1 cm = 0.01 m 2.54 cm = 1 inch 1 mm = 0.001 m

SOME COMPARISONS LENGTH: A DIME IS 1 mm THICK A QUARTER IS 2.5 cm DIAMETER AV. HEIGTH OF ADULT MALE 1.8 m MASS: A NICKEL IS 5 g A 120 lb PERSON HAS A MASS OF 55 kg VOLUME: A 12 oz SODA HAS A VOLUME OF 360 ml

ANOTHER IMPORTANT MEASUREMENT IS TEMPERATURE. TEMPERATURE IS A MEASURE OF THE AVERAGE KINETIC ENERGY. THE HIGHER THE TEMPERATURE, THE FASTER THE PARTICLES THAT MAKE UP THE OBJECT ARE VIBRATING (SOLID) OR MOVING (LIQUID OR GAS). THERE ARE THREE TEMPERATURE SCALES THAT ARE USED – FAHRENHEIT, CELCIUS, AND KELVIN.

THESE SCALES DIFFER BY THE TEMPERATURES SELECTED FOR THE REFERENCE POINTS. THEY ALL USE THE SAME THREE REFERENCE POINTS: - THE BOILING POINT OF WATER - THE FREEZING POINT OF WATER - ABSOLUTE ZERO THE EXTERNAL PRESSURE IS 1 ATMOSPHERE (760 MM Hg) FOR THE BOILING POING AND THE FREEZING POINT.

From to Fahrenheit to Celsius to Kelvin ºF F (ºF – 32) * 5/9 (ºF-32)*5/9+273.15 ºC (ºC * 9/5) + 32 C ºC + 273.15 K (K-273.15)*9/5+32 K - 273.15 THE CONVERSION EQUATIONS REFLECT THE DIFFERENCES IN NUMBER OF DEGREES BETWEEN THE REFERENCE POINTS AND THE VALUES SELECTED FOR THE REFERENCE POINTS.

SOME OF THE EQUIPMENT WE WILL USE

12 grams ANY MEASUREMENT HAS TWO PARTS – A NUMBER AND A UNIT. number units WE REPORT A MEASUREMENT BY RECORDING ALL THE CERTAIN DIGITS PLUS THE FIRST UNCERTAIN DIGIT. THESE ARE CALLED SIGNIFICANT FIGURES.

WHEN YOU ARE DOING AN EXPERIMENT, YOU SHOULD RECORD YOUR RESULTS TO THE APROPRIATE NUMBER OF SIGNIFICANT FIGURES – THIS WAY, THE UNCERTAINTY IN MEASUREMENT WILL BE KNOWN. FOR EXAMPLE, RATHER THAN WRITING 25 ml IF YOUR MEASUREMENT IS ACCURATE TO THE NEAREST 0.01 ml, YOU WOULD WRITE 25.00 ml

A COUPLE OF TERMS YOU WILL HERE IN REFERENCE TO MEASUREMENTS ARE: ACCURACY – REFERS TO THE AGREEMENT OF A PARTICULAR VALUE WITH THE TRUE VALUE. PRECISION – REFERS TO THE DEGREE OF AGREEMENT AMONG SEVERAL VALUES.

http://www.chem.sc.edu/faculty/morgan/resources/sigfigs/index.html THIS IS A TUTORIAL ON THE USE OF SIGNIFICANT FIGURES. WORK THE FIRST 10 SAMPLE PROBLEMS.