Measurement is at the heart of science. Without measurements to support or reject a hypothesis, science is simply conjecture - no better than crsytal balls and magic potions. many things can be measured: Consider any object, we can measure its

  • mass
  • temperature
  • volume
  • length
  • density
  • color
  • charge
  • melting point
  • boiling point
  • hardness
  • molecular weight
    and so on. The measurement of most quantities have units attached to them. howeverm the matter is compicated by the fact that several units can describe the same quantity, e.g., we can measure length by inches, centimeters, meters, yards, kilometers, miles etc. in order to aviod world-wide confusion, scientists decided to settle on a certain set of units to express basic quantities - the so-called fundamental units
    The Fundamental Units

    Mass - kilogram (kg)

    Length - meter (m)

    Time - second (s)

    Temperature - Kelvin (K)

    Charge - Coulomb (C)

    All other units are combinations of these units and are called "derived" units.



     speed  length  m/s
     volume  length+3  m+3
     energy mass length2/time2  kg m2/s2
     density  mass/volume  kg/m3
     force mass length/time2  kg m/s2
     pressure mass/length time2  kg/m s2
    Volume is an especially important quantity since it can be readily measured. Volume always has the units of a cubic length. the relationship between m3, dl and ml (cc) is readily understood from the diagram below

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    C101 Class Notes
    Prof. N. De Leon