How Do Scales Work?

How Do Scales Work?. Part of the series: Chemistry & Biology. Scales are used to measure the mass or weight of a substance, and scales are usually separated into balances and spring scales. Find out how spring scales rely on the stretching or compressing of a spring with help from a science teacher and field biologist in this free video on scales and balances. Read more: http://www.ehow.com/video_4801917_do-scales-work_.html