A “balance scale” is an item that is takes a measurement to determine the weight of an item. It has been around for hundreds of years and indeed, was the first device used to give a numerical to an item’s weight. It is an incredibly accurate piece of equipment, despite its age. The basic idea is that there are 2 pans hung from a horizontal bar that is supported exactly in the middle by a pivot point. You put the item on one of the pans and begin to add specified weights to the other side until the two sides are level. At this point, you would count the weight you added to the other side and that would be the weight of the item.
Historical Appearances
It is known to be the first means used to measure the weight of a device. Archaeologists have found examples of balance scales dating back as far as 500bc. There have been examples as old as this found in both Mesopotamia and also in Egypt. These scales were not necessarily used to give an exact weight of an object but a relative weight to another object. You also often see balance scales depicted in the Wild West during the gold rush. They were often used to measure the weight of gold that prospectors found, or indeed for trade. In the films, you will see the assayer’s office with a balance scale in it. He will have a weight on one side and be scooping gold dust into the other.
Accuracy
Balance scales are considered to be one of the accurate ways of measuring the weight of an item. Its advantage lies in the fact that it is not affected by gravity as it measures one item against the other. It can measure in any unit that you have a fixed weight for, including pounds, grams, ounces etc. It is important to note that its measurements are output in mass.
Pros and Cons
The biggest benefit of balance scales is that they are very accurate. It is as accurate as the “fulcrum” is loose. Another main advantage is that it requires no power source or outside energy. This means it can be used anywhere, such as at an excavation, or anywhere. They also require very little maintenance. They are however only as good as the materials they are made from. Any decrease in performance for the fulcrum us directly proportionate the decrease in accuracy. They also need to be kept clean as dirt can skew any readings you are taking. You also need to look after the weights as any dirt or chips from them will reduce the accuracy of the reading again.