Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Supplemental units for highschool and college physics courses

  1. Apr 12, 2003 #1


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    I'd welcome some ideas for names for a supplemental system of units to use in general physics coursework.
    I think there is room for an alternative system in which the values of c, G, and hbar are a billion, a billionth, and a nonillionth, with the elementary charge, Avogadro number, gas constant, and Boltzmann k having similar values as well.


    To be specific, suppose we make the time unit 54 milliseconds and define the rest of the base units by stipulating the following exact values of the fundamental constants:

    elementary charge, e---E-15
    Boltzmann k---E-18

    While these values are exact by definition, the value of G turns out to be 1.00E-9, in other words approximately one billionth. Making G a power of ten essentially forced the time unit to be what it is (up to a power of ten factor) and as such the time unit has an additional feature that 1600 thousand of them make one 86400-second day. What are needed are NAMES for the units resulting from specifying these values for the fundamental constants. Any ideas are welcome. It may suggest names if you know the sizes of the units.


    Here are the approximate sizes of the units resulting from the stated values of the natural constants:

    length unit---1.6 cm
    mass unit---22 gram
    force unit ---1/8 of a newton
    energy unit---2 millijoules
    charge unit---quadrillion (E15) electrons, a sixth of a metric millicoulomb
    voltage unit ---12 conventional volts
    current unit ---3 milliamps
    power unit ---36 milliwatts
    temperature step ---141 kelvin

    If you don't like those sizes you are welcome to change them by powers of ten. For example 100 times the length unit is 1.62 meters: the length of a classical pace a thousand of which is 1620 meters or about one mile. Adjusting the sizes of the units by powers of ten merely entails specifying different power-of-ten values for the fundamental constants---making c be E7 instead of E9 and suchlike changes.

    I'd like to make the alternative system easy to learn and fun to use---and have it available on the web for physics teachers to try out. It might be helpful to post a sampling of physics problems stated in the new units.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?