torsion balance

views updated May 08 2018

torsion balance A weighing instrument in which the required weight of a sample is set by rotating a lever to move a needle to the appropriate position on a graduated scale, and then the sample is added to the weighing pan, a little at a time, until it counterbalances the pre-set weight precisely and the needle is brought back to the ‘zero’ position. This is a useful and rapid technique when large numbers of routine weighings need to be performed in the range of 0.01–5.0 g.