A weighing scale (usually just "scales" in UK and Australian English, "weighing machine" in south Asian English or "scale" in US English) is a measuring instrument for determining the weight or mass of an object.
A spring scale measures weight by the distance a spring deflects under its load. A balance compares the torque on the arm due to the sample weight to the torque on the arm due to a standard reference weight using a horizontal lever. Balances are different from scales, in that a balance measures mass (or more specifically gravitational mass), where as a scale measures weight (or more specifically, either the tension or compression force of constraint provided by the scale). Weighing scales are used in many industrial and commercial applications, and products from feathers to loaded tractor-trailers are sold by weight. Specialized medical scales and bathroom scales are used to measure the body weight of human beings.
Read more about Weighing Scale: History, Balance, Testing and Certification, Supermarket/retail Scale, Sources of Error, Symbolism
Famous quotes containing the word scale:
“The most perfect political community must be amongst those who are in the middle rank, and those states are best instituted wherein these are a larger and more respectable part, if possible, than both the other; or, if that cannot be, at least than either of them separate, so that being thrown into the balance it may prevent either scale from preponderating.”
—Aristotle (384–322 B.C.)