Measurements The Metric system was developed in France during the Napoleonic reign of France in the 1790's. 1

“Weights and measures may be ranked among the necessaries of life to every individual of human society…They are necessary to every occupation of human industry.... The knowledge of them, as in established use, is among the first elements of education...” JOHN QUINCY ADAMS - Report to the Congress, 1821

Which other countries, besides the U.S., do not use the metric system? According to a survey taken many years ago, the only other countries that have not officially adopted the metric system are Liberia (in western Africa) and Myanmar (also known as Burma, in Southeast Asia). STAT FACT 2

Accurate Measurements Be sure we can compare our measurements to other people. Scientists make repeated measurements to increase the validity and reliability of the results. 3 Accurate=how close the measurement is to the actual measurement.

Accuracy vs. precision Precision: When taking the same measurement over and over you get the same results. Accuracy: How close your results are to the TRUE/REAL results Y O U C A N B E P R E C I S E B U T S T I L L B E W R O N G. 4

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A Measurement system 1.must be agreed upon and 2.cannot change Ex: The foot. 6

Scale units  Metric system attempted to do away with the confusing multiplicity of measurement scales by reducing them to a few fundamental ones.

Le Systeme Internationale d’Unites (SI) 1960 Based on Metric System 7

Standards Exact quantity that people agree to use for a certain measurement. Ex: The meter The speed that light travels in a vacuum 1/ of a second. Why….This seems CRAZY!!! The meter ClipThe meter 8

Another Example of a Standard …..The kilogram The official kilogram, made of platinum-iridium, remains in France at the International Bureau of Weights and Measures Clip 9

Le Systeme Internationale d’Unites (SI) English: International System of Units Each measurement has a base unit. 10

SI System Based on multiples of ten. Examples of base units Length –Meter Mass –Gram Volume –Liter Time –Second 11 Temperature -Kelvin Energy -Joule Electric Current -Ampere

Prefixes Prefixes are used with the base units to indicate what multiple of ten should be used.Prefixes are used with the base units to indicate what multiple of ten should be used. The most common prefixes are:The most common prefixes are: Prefix- Symbol Multiple Prefix- Symbol Multiple Kilo-k1,000 Kilo-k1,000 Hecto-h100 Hecto-h100 Deca-D10 Deca-D10 Deci-d.1 Deci-d.1 Centi-c.01 Centi-c.01 Mili-m.001 Mili-m BASE UNIT

Metric Conversions A conversion is changing the way you state the same amount!A conversion is changing the way you state the same amount! Ex: 1 dollarEx: 1 dollar –4 quarters, 100 pennies, 10 dimes 1meter = 100centimeters1meter = 100centimeters Simply move your decimal point.Simply move your decimal point.

Convert the Following 1)65ml=_____L 2)3948g=_____kg 3)389.59m= ______km 4) mg=_____kg (use Sci. Not.) 5)89304µg= _______g Scientific Notation: a method of writing, or of displaying real numbers as a decimal number between 1 and 10 followed by an integer power of 10

Laboratory Apparatuses for making Measurements 13

Distance 14

Meter Stick 1m = 100 Centimeters1m = 100 Centimeters 1m = 1000 millimeters1m = 1000 millimeters 1cm = 10 mm Length Distance 1515 Each line on the meter stick is a millimeter.

Meter Stick 1616 The last digit in all measurements is an estimate digit.

Amount of matter in an object 17

Triple Beam Balance Grams = g 1818

Space occupied 19

Length width Height Length x Height x Width =Volume 20

Graduated Cylinder Volume Space an object occupies 2121

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Kinetic Energy 1226

Temperature Fahrenheit vs. Celsius vs. Kelvin 1742, Anders Celsius ( ) 1714:Daniel Gabriel Fahrenheit ( ) Lord Kelvin ( ) Superfridge

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Mass per unit Volume 29

Derived Units Obtained by combining different units. Ex: Density Density is the amount of mass per unit volume. D = m/v 30

Remember all measurement need a unit.

TYPES OF DATA Quantitative vs. Qualitative If the data collected involve observations without measurements or numbers, then it is referred to as qualitative data. Quantitative data involves numbers or measurements. 31

Significant Figures For measured numbers, significant figures relate the certainty of the measurement. As the number of significant figures increases, the more certain the measurement. 32 The number of significant figures is the number of digits believed to be correct by the person doing the measuring.

Your answer cannot be more accurate than the equipment used to make the measurement. The accuracy of the result is limited by the least accurate measurement. 33

Sig Fig Rules Nonzero digits are always significant All final zeroes after a decimal point are significant Zeroes between two other significant digits are always significant Zeroes used solely as placeholders are NOT significant Zeroes between a decimal point and a nonzero digit are significant. 34

Examples The significant zeroes in these measurements are colored black and the insignificant zeroes are red. 1) ) ) )18,000 5)18, ) Want to make it easier????? Put it in Scientific Notation. 35

Practice How many Sig Figs? _____ _____ _____ _____ _____ _____ _____ 36

Arithmetic When you perform any arithmetic operation, it is important to remember that the result can never be more precise than the least precise measurement. 37

Addition or Subtraction 1.Perform the operation. 2.Round off the result to correspond to the least precise value involved. ((fewest # of decimal places) 3.Example: m m m = m **You will report the correct calculated answer as m. 38

1.Perform the operation. 2.Round off the result to correspond to the number with the LEAST number of significant figures. 3.Example: 3.22 cm x 2.1 cm = cm 2 **Reported answer: 6.8 cm 2 Multiplication & Division Rules 39

Practice 1) cm cm cm cm = 2) 1.6 km m cm = 3) g g = 4) m m = 5) m m = 6) 131 cm x 2.3 cm = 7) m x m = 8) 20.2 cm / 7.41 s = 9) g / ml = 40

Dimensional Analysis Problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. Examples: –Convert 50.0 mL to liters. –How many centimeters are in 6.00 inches? –Express 24.0 cm in inches. –How many seconds are in 2.00 years? 41

Temperature Conversion Examples on Notes. K = º C º C = ( º F - 32) ÷ 1.8 º C = K º F = 1.8 ºC

Answers 1) -23 ºC 2) 66 ºC 3) 290 K 4) 328 K 5) 31.9 ºC 6) 230 ºF Temperature Conversion