There are seven different Standardised International (SI) units of measurements from which all others are derived. These are:

 Name Phenomenon Units meter Length m second time s kilogram mass kg ampere electric current A kelvin thermodynamic temperature K mole Amount of substance mol Luminous intensity candela cd

There are 22 derived physical phenomena, shown below. The names, phenomena, units and base units have been mixed up.

1. Sort them into the correct order and work out how their units may be represented with base SI units.
2. For each pheonomena, how many examples of biological application can you find? Can you find an example from biology for each one of these processes?
 Name Phenomenon Units Base units becquerel, Bq capacitance A / V $\quad\quad$m$^2$m$^{-2}$cd degrees Celsius, $^\circ$ C electric conductance C / V $\quad\quad$K coulomb, C electric potential cd sr $\quad\quad$kg s$^{-2}$ A$^{-1}$ farad, F electric resistance J / kg $\quad\quad$m kg s$^{-2}$ gray, Gy electrical charge J / kg $\quad\quad$m$^{1}$m$^{-1}$ henry, H energy J / S $\quad\quad$m$^{2}$ m$^{-4}$ cd Hertz, Hz flux of light $\quad\quad\quad$lm / m$^2$ $\quad\quad$m$^{2}$ kg s$^{-2}$ joule, J force $\quad\quad\quad$N / m$^{2}$ $\quad\quad$m$^{2}$ kg s$^{-2}$ A$^{-1}$ katal, kat frequency N m $\quad\quad$m$^{2}$ kg s$^{-2}$ A$^{-2}$ lumen, lm illuminance V / A $\quad\quad$m$^{2}$ kg s$^{-3}$ lux, lx inductance V s $\quad\quad$m$^{2}$ kg s$^{-3}$ A$^{-1}$ newton, N magnetic flux W / A $\quad\quad$m$^{2}$ kg s$^{-3}$ A$^{-2}$ ohm, $\Omega$ magnetic flux density Wb / A $\quad\quad$m$^{-2}$ kg$^{-1}$ s$^{3}$ A$^{2}$ pascal, Pa plane angle $\quad\quad\quad$Wb / m$^2$ $\quad\quad$m$^{-2}$ kg$^{-1}$ s$^{4}$ A$^{2}$ radian, rad power $\quad\quad$m$^{2}$ s$^{-2}$ siemens, S pressure $\quad\quad$m$^{2}$m$^{-2}$ sievert, Sv radiation dose $\quad\quad$sA steradian, sr solid angle $\quad\quad$s$^{-1}$ tesla, T temperature $\quad\quad$s$^{-1}$ mol volt, V unit of catalytic activity watt, W weber, Wb

(data sourced from the Bureau International des Poids et Mesures http://www.bipm.org/)

### Other problems

Try Universal Time, Mass, Length to investigate the units implicit in the fundamental constants of nature.