Sound waves can be ranked by their intensity, I, given in the formula below, where r is the distance from the source of a sound with a power output of P.

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days