What Is the Difference Between a Weight Scale & a Balanced Scale?

The differences between a balance scale and a weight scale are commonly misunderstood because they both exist for the purpose of measuring weight. There are, however, a few distinct differences such as physical appearances, how they measure weight and what types of weight they can measure.

Balance Scale

• Balance scale

  A balance scale is most often characterized by its T-like shape. A horizontal beam, from which two baskets or plates are suspended, is loosely attached to a vertical pole. When completely empty these baskets or plates are identical in weight, which keeps the horizontal beam perfectly level and balanced on the vertical pole. However, when weight is unevenly added to the baskets or plates, the horizontal beam will dip toward the heavier side. Because of the balance scale's physical design, there are limits to what can be weighed with it. It is also more difficult to attest to the actual weight of an object without something to compare it to. This is often done by putting weights on one basket or plate and filling the other with the object to weigh and then adding or subtracting weights until the horizontal beam is level again.

Weight Scale

• Weight scale

  A weight scale is physically characterized as much simpler. These scales tend to be rectangular in nature---though others have more interesting designs---and are used to measure any number of items from a person to a peach. These scales do not require anything other than the item to be weighed and usually respond with either a digital number or a physical indication---such as a pointer on a dial of numbers---of the weight.

The History of Scales

• According to Avery Weigh-Tronix, the first scales were conceived and used at the height of ancient Egyptian civilization. Using different plant seeds and grains for small amounts and stones equivalents for larger, they established a weight system to establish prices as well as the worth of an object. From there, the Romans contributed by creating pound weights, which England elaborated on by establishing different weights for different goods. These different weights would later become the units that are commonly used today, such as ounces.

  Just as the weight and its value were carefully refined and developed, so were the actual scales. Avery Weigh-Tronix states that balance scales, used as early as 4000 B.C., would eventually give way to weight scales, first designed by Leonardo Da Vinci and improved upon ever since. With the discovery of electricity and the incorporation of electronics, the weight scale is now extremely common and used in everyday society.