A Balance is an instrument for determining weight using suspended scales. It consists of a bar with a fulcrum in the center and at each end a scale hook or pan is suspended, one holding the object to be weighed and the other holding an object or weights. When the weight is the same on both sides the point or support falls into place and is shown as a straight line or 90º. The following photos show two types of balance used to weigh different material of different proportions.
The last balance has a rigid horizontal beam supported at its center with weighing plates hung at both ends and perfectly balanced. A weight is put on one side, the substance being weighed on the other and when the beam is level, the amount is correct. This balance is used for measuring small quantities of up to 10g.