The erg is the standard unit of energy in the centimeter-gram-second ( cgs ) or small-unit metric system . It is an amount of energy equivalent to that expended by a force of one dyne acting over a distance of one centimeter . This is a small unit of energy, equivalent to 0.0000001 (one ten-millionth) of a joule . To convert from joules to ergs, multiply by 10 7 . Conversely, multiply by 10 -7 .
It has been suggested that 1 erg is approximately the amount of energy required for a mosquito to take off. This unit is seldom used today, but it can be found in some older scientific literature, especially in Europe.