The Determination of the Volumes of Felted Wool Balls

Abstract

Two methods of determination of the volumes of felted wool balls with considerable accuracy are described. The first is an indirect method by computation from the directly determined average diameter of a ball, and a measuring procedure is given whereby this average diameter can be obtained accurately even when the shape of the ball is not per fectly spherical. However, the method involves subjective personal judgment and hence suffers from some lack of precision due to operator errors which may be introduced. In the second method, the volume is determined directly by saturating the ball with water and weighing it in this condition; theory and practice are fully described. The method is simple, very accurate (± 0.01 cm3), free from operator bias, and requires only normal laboratory equipment.