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Published byGrant Ward Modified over 9 years ago
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Measurements are quantitative information. They include numbers AND units.
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Quantity = has magnitude, size, or amount Quantity ≠ measurement! Ex. The quantity, volume, is represented by measurements reported in units like teaspoons, milliliters, cubic centimeters, gallons, quarts, etc.
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Agreed upon measurement of a quantity Ex. The foot
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Scientists worldwide use the metric system of measurement SI has 7 base units (see table 1 and KNOW these quantities, units, and abbreviations) NEVER use commas when writing numbers (too easily confused with decimals)
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Length (l)meter (m) Mass (m)kilogram (kg) Time (t)second (s) Temperature (T)Kelvin (K) Amt. of a substance (n)mole (mol) Electric current (I) ampere (A) Luminous intensity (I v ) candela (cd) QuantityUnit
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Measure of the amount of matter (stuff) Does NOT change with location Weight DOES change depending on gravity I weigh less on the moon, but my mass does NOT differ from my mass on Earth.
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Prefixes added to base units are used to represent quantities larger or smaller than the base unit. Ex. 1 centimeter is 1/100 th of a meter 1 cm = 0.01 m OR 1 cm = 1 X 10 -2
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KNOW THESE prefixes!!!!!!! Know the abbreviation for each prefix Know the conversion factor (example) for each prefix Know that these prefixes can be applied to ANY base unit
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A ratio (fraction) expressing the equality btw two different units Can be used to convert from one unit to the other Ex. 4 quarters12 inches 1 dollar1 foot
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Express 17.5g in mg. Express 45 km/hr in m/s. This is called Dimensional Analysis
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Derived units are combinations of SI base units AreaAl x wm 2 VolumeVl x w x hm 3 Density Dm/Vkg/m 3 Molar massMm/amtkg/mol Molar volumeVmV/amtm 3 /mol EnergyEforce x lengthjoule (J)
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The amount of space occupied by matter Liquid volume is measured in liters (L) 1 L = 1000 cm 3 1 mL = 1 cm 3 (cubic centimeter or cc)
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Ratio of mass to volume Amt of “stuff” / amt of space taken by stuff Density = how crowded the particles of matter are Be sure to read about density and see table 4 on page 38!!!
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