DISCOVER

# Types of Weight Scales

Updated April 17, 2017

There are many types of scales in use today. Weight scales are used to measure the weight of many objects. Scales range in size from very small, used in weighing objects that are small and lightweight, to huge scales that are used to weigh massive objects. Weigh scales can be found being used in many industries, from hospitals and grocery stores to factories and construction sites.

## Spring Scale

Spring scales employ springs that are under tension in order to measure the weight of an object. When an object is placed on this type of scale, the springs are compressed, the tension on the springs is measured and an output is produced. This type of scale can output information in either metric or standard weight. They come in sizes that can measure from ounces all the way to hundreds of pounds. They come in models that can have an analogue or digital LED readout. Spring scales are not the most accurate type because they rely on gravity and tension to determine weight. Gravity can be different depending on location, and tension can be different depending on the age of the springs. This type of scale is fine for daily home uses.

## Balance Scale

The balance style of weight scale is what is normally found in a doctor's office. This type of scale uses a beam that rest on a fulcrum and two or more sliding weights. The object being weighed, which is normally a person, is the counter weight. This type of scale uses the known weight of the sliding weights and the weight of the counter weight to determine the weight of the counter weight. The object is placed on the scale and the sliding weights are moved along the beam until perfect balance is found. Once the beam is balanced perfectly on the fulcrum, the numbers on the beam are read and the weight is determined. This type of scale is very accurate, and although it is commonly seen in the medical profession, various types of this scale can be found in use in other industries.

## Hydraulic Scale

The hydraulic scale uses hydraulic fluid to determine the weight of an object. When an object is placed on the scale, the hydraulic fluid is displaced and the scale reads this displacement and determines the weight of the object. These scales can be found in many places but they are generally used in industries that need to weigh large objects. This is the type of scale that is seen along American highways at weigh stations. Hydraulic scales are very accurate. Weigh stations used large spring scales in the past, but most of them have been replaced with more durable and accurate hydraulic scales.

## BMI Weight Scale

The BMI weight scale is a scale that takes the weight of a person and turns that weight into a Body Mass Index, which tells a doctor how much fat is in a person's body. This is useful information when it comes time for a doctor to help a patient lose weight and live a healthier life. The doctor will input the height and other factors of the patient into the scale and then have the patient stand on the scale. The scale then takes the height, weight and other factors and gives the doctor a BMI reading and not just a weight reading.