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DO NOWHow are SI units of measurement different from other units of measurement we use in the US (such as feet, gallon, miles, pounds etc.)? What are the SI units of measurement for: LengthVolumeMassTimeTemperature3. What tools or devices are used to make measurements: LengthVolumeMassTimeTemperature

1SI system uses prefixes so scientists do not have to write a lot of decimal places and zeros

For example, compare: Thickness of a strand of hair: .00009mThickness of a page: .0001mDistance from your house to your friends house: 20 metersDistance from here to China: 11,000,000 meters

Scientists convert, or change, SI units to smaller or larger units using factors (or ratios)

Taking a step backLets focus on these two concepts for the rest of the period2Using prefixes in measurements Prefixes hold places of decimals and zerosExample, the prefix kilo- holds the place of three 0s in 1000 base units 1 kilometer = 1000 metersThe prefix centi- holds two places after the decimal point in .01 base units1 centimeter = .01 meter3The prefixes arekilo- hecto - deca- [base unit] deci- centi- milli-Larger Smaller

Symbols for the prefixes are: k- h- da- [b. u. abbv.] d- c- m-

When writing measurements, the first letter stands for the prefix, the second letter stands for the unit of measureExample, kL = kiloliter, mm = millimeter4Lets practice!!!!Write out the units of measurement for the following:Ex. mm = millimeter1) mL 2) dag 3) dL 4) hm 5) dg 6) hL 7) kg

Abbreviate the following units of measurements:Example: cm = centimeter1) hectometer 2) decagram 3)milliliter4) decigram 5) kilometer 6) centimeter

5FACTORS OF 10SymbolPrefixMultiples of base unitExamplem-milli-.0011 millimeter =.001 meterc-centi-.011 centimeter = .01 meterd-deci-.11 decimeter = .1 meter-(base unit)1meterda-deca-101 decameter= 10 meterh-hecto-1001 hectometer = 100 meterk-kilo-10001 kilometer = 1000 meterAbbreviate the following units of measurements:Example: cm = centimeter1) hectometer 2) decagram 3)milliliter.4) decigram 5)

6CONVERTING between units.1. Moving decimal places:Example: convert 275 kg to ____gkilo- hecto - deca- [base unit] deci- centi- milli-

Moved three prefixes to the right from kilogram to grams, move three decimal places to the right275.000 kg = 275000g

7Lets Practice! Moving decimals!kilo- hecto - deca- [base unit] deci- centi- milli-

Covert the following units as indicated:1) 232m = 2.32 hm 2) 4.24 km = 4240 m3) .039m = 39 mm 4) 923 dam = 9230 m5) 2.3m = 230 cm 6) 239 dm = 23.9 m8CONVERTING between units2. Using conversion factors:

GIVEN x CONVERSION FACTOR = UNKNOWNConversion factors are determined using relationship between the units involved. Example: 1 millimeter = .001 meter

Conversion factors are the ratios of the units involvedExample: 1millimeter .001meter .001meter 1 millimeter

9CONVERTING between units2. Using conversion factors:

GIVEN x CONVERSION FACTOR = UNKNOWNExample: 3.89 dag = 38.0 g Relationship between units: 1 dag = 10 g

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