Measurement of Weight
Instruments for weighing materials are called balances, and most laboratories have more than one type of balance, depending on the amount of material being measured and the degree of accuracy required.
a. Mechanical balances – Mechanical balances weigh an object ona pan hanging from a beam that has a counterbalanced weight. We do not use mechanical balances in our lab.
b. Electronic balances – Electronic balances have replaced mostmechanical balances due to their greater accuracy and ease of operation. They are easier to use because they usually have a digital readout, and weighing dishes can be tared to read zero mass before using. Most balances used for preparation of solutions have a sensitivity of +/- 0.01 g, but electronic analytical balances can be sensitive to +/- 0.1 mg or less. Electronic balances require routine maintenance and recalibration.