Powerpoint Measurements

7/27/2019 Powerpoint Measurements

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http://upload.wikimedia.org/wikipedia/commons/8/82/Measuring_Tape_Inch+CM.jpg


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Measurement is observationmade more specific bycomparing some attributesof a system to a standard ofreference


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Measurement consists of anumerical value and a unitof measurement to whichthe number


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Measurement is the processor the result of determiningthe magnitude of aquantity, such as length ormass, relative to a unit ofmeasurement.


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SYSTEMSOFMEASUREMENTS


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1) English units2) Metric or SI

units


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The International System of Units(abbreviated SI from the FrenchLe Systme International d'Units)is the modern form of the metricsystem.


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Two types of SI units1) Base units.2) Derived units


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Base units are the simplemeasurements for time,length, mass, temperature,amount of substance,electric current and lightintensity.


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Name Unit symbol Quantity Symbolmetre m length l (a lowercase L)kilogram kg mass msecond s time tampere A electric current I (a capital i)kelvin K thermodynamic

temperatureT

candela cd Luminousintensity

Iv (a capital iwith lowercase vsubscript)

mole mol Amount ofsubstance

n
http://upload.wikimedia.org/wikipedia/en/c/c8/SI_base_unit.svg


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SEVENBASEUNITS
http://upload.wikimedia.org/wikipedia/en/c/c8/SI_base_unit.svghttp://upload.wikimedia.org/wikipedia/en/c/c8/SI_base_unit.svghttp://upload.wikimedia.org/wikipedia/en/c/c8/SI_base_unit.svg


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Derived units areconstructed from the baseunits, for example, thejoule ( J ) , i.e. the unit forenergy or work, is definedfrom the base units as N.mor N m
http://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unit


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Derived units from SI base units

Name Symbol Quantity

meter2 m2 area

meter3 m3 volumemole/meter3 mol/meter3 concentration

newton N Forcesievert Sv equivalent dose(ofionizing radiation)
http://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/Sieverthttp://en.wikipedia.org/wiki/Equivalent_dosehttp://en.wikipedia.org/wiki/Equivalent_dosehttp://en.wikipedia.org/wiki/Ionizing_radiationhttp://en.wikipedia.org/wiki/Ionizing_radiationhttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/Ionizing_radiationhttp://en.wikipedia.org/wiki/Equivalent_dosehttp://en.wikipedia.org/wiki/Sieverthttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unithttp://en.wikipedia.org/wiki/SI_derived_unit


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1) Mass- triple beam balance2) Length meterstick,ruler3) Volume graduated

cylinder4) Time stopwatch5) Electric current- ammeter


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1) Symbols do not have anappended period/full stop (.).Example : kg , m , s2) Symbols are written inupright Roman type like mfor metres, s for seconds)


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(so as to differentiate fromthe italic type used forvariables (m for mass, s fordisplacement).


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3) All symbols of prefixeslarger than 103 (kilo) areuppercase. Ex: M= 1064) Symbols of units are notpluralised, for example"25 kg" (not "25 kgs ).


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The ANIST has definedguidelines pluralising unitnames: the plural isformed by using normalEnglish grammar rules,for example, "henries" isthe plural of " henry


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The units lux, hertz, andsiemens are exceptions fromthis rule: They remain thesame in singular andplural.This rule applies onlyto the full names of units,not to their symbols.


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5) A space separates thenumber and the symbol;e.g.,"2.21 kg","7.3102 m2""22 K". This rule explicitlyincludes the percent sign(%).


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Exceptions are the symbolsfor plane angular degrees,minutes and seconds(, and ), which are placedimmediately after thenumber with no interveningspace.


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6) Spaces may be used as athousands separator (1 000000) in contrast to commasor periods (1,000,000 or1.000.000)


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7) Symbols for derived units(formed from multiple unitsby multiplication) are joinedwith a center dot (), dot(.),or a non-break space,for example, "Nm", "N.m",or "N m.


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8) Symbols formed bydivision of two units arejoined with a solidus (), orgiven as a negative exponent.

Example : 2.5 km/sec or2.5 km sec -1


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For example, the "metre persecond" can be written"ms", "m s1 never ms-1,or "ms1 Only onesolidus should be used;e.g., "kg(ms2)" or"kgm1s2


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RECORDINGMEASUREMENTS


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are measurements whichconsist of digits known withcertainty plus the firstuncertain digit.


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Significant figures arecritical when reportingscientific data because theygive the reader an idea ofhow well a data wasactually measured orreported


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1) ALL non-zero numbers(1,2,3,4,5,6,7,8,9) areALWAYS significant.2) ALL zeroes between non-zero numbers are ALWAYSsignificant.

Example : 2005 cmRULES for significant figures


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3) ALL zeroes which areSIMULTANEOUSLY to the rightof the decimal point AND atthe end of the number areALWAYS significant.Example: 2.0090


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4) ALL zeroes which are tothe left of a writtendecimal point and are in anumber >= 10 areALWAYS significant.Example: 10.50 m


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A helpful way to check rules 3

and 4 is to write the number inscientific notation.

If you can/must get rid of thezeroes, then they are NOT

significant.


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5) Zeroes at the end of anumber may or may not besignificant.Example: 38003.800 x 1033.80x 1033.8 x 103


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If zero merely locates thedecimal point , it is notsignificant.Example: 80 kg, 0.250 mA zero before first non zerodigit is not significant.

Example: 09.50 cm


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. Number48,9233.967

900.060.00048.1000501.0403,000,000

Examples:

How many significant

figures are present in

the following

numbers?


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.ADDITION AND SUBTRACTION:When adding or subtractingnumbers, count the NUMBEROF DECIMAL PLACES todetermine the number of

significant figures.


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.ADDITION AND SUBTRACTION:The number with the lowest

decimal place determines theplace of the last significant figure

in the answer


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.ADDITION AND SUBTRACTION:Example :

2.4 + 3.20 =

4.50 + 5.897 + 3.2987 =4.250 2.10 =


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.MULTIPLICATION ANDDIVISIONThe final answer musthave the same no. of SF as

the factor with the least no.of SF.Ex : 1) 2.45 x 3.206 2)42 / 6.00


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.ROUNDING OFF OF NUMBERS1. When the number to be

dropped is greater than 5,

increase the precedingnumber by one .

Example: 6.28


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.2. When the number to bedropped is 5 and thepreceding number is an

odd number, increase thepreceding number by one .

Example: 6.35


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.3. When the number to bedropped is 5 and thepreceding number is an

even number, retain thepreceding number.

Example: 6.25


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. Number # SignificantFigures Rule(s)48,923 5 13.967 4 1900.06 5 1,2,4

0.0004 (= 4 E-4) 1 1,48.1000 5 1,3

501.040 6 1,2,3,43,000,000 (= 3E+6) 1 110.0 (= 1.00 3 1,3,4

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Powerpoint Measurements