scale¹ / skāl/ • n. 1. each of the small, thin horny or bony plates protecting the skin of fish and reptiles, typically overlapping one another.2. something resembling a fish scale in appearance or function, in particular: ∎  a thick dry flake of skin. ∎  a rudimentary leaf, feather, or bract. ∎  each of numerous microscopic tilelike structures covering the wings of butterflies and moths.3. a flaky deposit, in particular: ∎  a white deposit formed in a kettle, boiler, etc., by the evaporation of water containing lime. ∎  tartar formed on teeth. ∎  a coating of oxide formed on heated metal.• v. 1. [tr.] remove scale or scales from: he scales the fish and removes the innards. ∎  remove tartar from (teeth) by scraping them.2. [intr.] [often as n.] (scaling) (esp. of the skin) form scales: moisturizers can ease off drying and scaling. ∎  come off in scales or thin pieces; flake off: the paint was scaling from the brick walls.DERIVATIVES: scaled / skāld/ adj. [often in comb.] a rough-scaled fish.scale·less / ˈskāl(l)is/ adj.scal·er n.scale² • n. (usu. scales) an instrument for weighing. Scales were originally simple balances (pairs of scales) but are now usually devices with an internal weighing mechanism housed under a platform on which the thing to be weighed is placed, with a gauge or electronic display showing the weight. ∎  (also scale·pan) either of the dishes on a simple balance.scale³ • n. 1. a graduated range of values forming a standard system for measuring or grading something: company employees have hit the top of their pay scales. ∎  a series of marks at regular intervals in a line used in measuring something: the mean delivery time is plotted against a scale on the right. ∎  a device having such a series of marks: she read the exact distance off a scale. ∎  a rule determining the distances between such marks: the vertical axis is given on a logarithmic scale.2. [in sing.] the relative size or extent of something: no one foresaw the scale of the disaster. ∎  [often as adj.] a ratio of size in a map, model, drawing, or plan: a one-fifth scale model of a seven-story building. ∎  (in full scale of notation) Math. a system of numerical notation in which the value of a digit depends upon its position in the number, successive positions representing successive powers of a fixed base: the conversion of the number to the binary scale. ∎  Photog. the range of exposures over which a photographic material will give an acceptable variation in density.3. Mus. an arrangement of the notes in any system of music in ascending or descending order of pitch: the scale of C major.• v. [tr.] 1. climb up or over (something high and steep): thieves scaled an 8-foot fence.2. represent in proportional dimensions; reduce or increase in size according to a common scale: [as adj.] (scaled) scaled plans of the house. ∎  [intr.] (of a quantity or property) be variable according to a particular scale.3. estimate the amount of timber that will be produced from (a log or uncut tree).PHRASES: play (or sing or practice) scales Mus. perform the notes of a scale as an exercise for the fingers or voice.to scale with a uniform reduction or enlargement: it is hard to build models to scale from a drawing.PHRASAL VERBS: scale something back reduce something in size, number, or extent, esp. by a constant proportion across the board: in the short term, even scaling back defense costs money.scale something down (or scale down) reduce something (or be reduced) in size, number or extent, esp. by a constant proportion across the board: manufacturing capacity has been scaled down his whole income scaled down by 20 percent.scale something up (or scale up) increase something (or be increased) in size or number: one cannot suddenly scale up a laboratory procedure by a thousandfold.DERIVATIVES: scal·er n.ORIGIN: late Middle English: from Latin scala ‘ladder’ (the verb via Old French escaler or medieval Latin scalare ‘climb’), from the base of Latin scandere ‘to climb.’

Scale

Background

The traditional bathroom scale is used to measure a person's body weight. It is based on a spring system that uses the weight of the person to depress a lever, which in turn rotates a sprocket attached to the dial. The dial rotates until it stops, and a plastic marker marks the person's weight. A home-use bathroom scale has a margin of error of ±0.25 lb (±0.12 kg). Scales for bathrooms or kitchens are generally designed as spring balances.

History

Units of measurements have been used for all of antiquity. People have always used some type of set standard for trade. The first known measurement device was used by the Romans 2,000 years ago. They devised an equal beam scale which was shaped like the letter T with both arms measuring 7.4 in (18.8 cm) wide. Attached to each arm were metal pans that were typically 1.5 in (4 cm) in diameter.

The first known unit of weight was the wheat seed. The ancient Romans and Greeks used this standard to measure any other object against, generally for barter or trade. For instance, farmers would bring their crops to sell and they would be weighed against the known standard of wheat grain. X-amount of produce was equal to X-amount of grain needed to maintain the equilibrium of the balance. The Arabs improved on these techniques and established weight standards for gold, silver, and gems.

By the thirteenth century trade had become much more widespread, but people in different parts of the world (or even within the same country) used different standards of measurement. King Edward I of England established a base standard of measurement to which objects or materials could be compared to. This standard soon traveled through trade and became somewhat acceptable in other parts of the world.

In 1793, the French government devised a system based on a line running along the ground through Paris that measured the distance from the North Pole to the Equator. The French called this the metric system. People were unfamiliar with this system and it was not fully enforced until 1837 when it became the standard in European countries.

Scales themselves continued to evolve to meet both the distributor and customer's needs. Customer's wanted to be able to count on the accuracy of the distributor's scales to make sure that they were not being cheated. The first scales used a simple balance beam to weigh an object against a known standard.

The first spring balance was brought into widespread use in the eighteenth century. In Bilston, England Richard Salter began making what is today known as a fisherman's scale which used a spring balance to measure weight. The Salter brand was also the first company in England to marked bathroom scales. Modern home scales have evolved from these early industrial prototypes. Today, the scale is based on the same spring balance idea.

Raw Materials

The case of the spring scale is manufactured from stainless steel or aluminum. The interior is composed of metal springs, pins, gears, and plastic. The gears can be made from aluminum, copper, brass, bronze, stainless, steel, nickel silver, monel, zinc, iron, or plastic. The non-slip mat is formed from a mix of poly vinyl chloride and rubber.

Design

There are many different types of scales; solar, electronic, digital, and spring to name a few. The scales may also differ on what they measure. Some scales are able to measure a person's body fat ratio. The color and size of scales vary greatly to meet all customer needs.

A typical spring scale is comprised of weight transmitting levers, a weight sensing mechanism, and dial enclosed in a metal casing. Generally, the scale is equipped with a non-slip pad on the platform so that the person does not slip and fall off the scale.

The Manufacturing
Process

• 1 Aluminum is melted until molten and then fed into a die that has the desired shape of the scale casing. The aluminum is cast in a cold chamber process at temperature of 1,202°F (650°C) so it will not bond with the steel die.
• 2 The aluminum is then cooled and ejected from the mold. Both the top and bottom of the scale body are manufactured using this process.
• 3 The top of the case is manufactured with a slot missing that will serve as the window through which to view the correct weight. This plastic covering is made from molted plastic fed into an injection molding machine. The plastic is then injected into a mold of the cover and left to cool. After cooling, the cover is removed and manually inserted into the top casing.
• 4 There are four levers used to distribute a person's weight through the scale. The levers are manufactured from thin sheets of aluminum or steel that is delivered to the plant. The sheets are then placed on a conveyor belt to be laser cut. A laser beam that is 0.008 in (0.2 mm) in diameter focuses 1,000-2,000 watts on the aluminum sheet. The laser gets the outline of the lever and instructions from a Computer Aided Drafting and Design (CAD) drawing.
• 5 The springs, brackets, and gears arrive preformed at the plant. They are inspected for quality and then distributed to work stations along an assembly line.
• 6 The dial is formed from a coining method. In this process the aluminum is placed in a set of dies that close, exerting up to 200,00 psi (1,375 mpa) depending on the level of detail on the dial.
• 7 The dial is then extracted and automatically painted, typically white with black numbers.
• 8 The non-slip pad is made from a mixture of polyvinyl chloride (PVC) and rubber. The resin is measured and mixed, then poured into the mold of the non-slip mat. The mold is then cured and the finished slip mat is removed.

Putting it all together

• 9 The case is then placed on a conveyor belt and the metal plate that holds the main lever and the spring is fitted through a slot that was molded into the side of the case.
• 10 The main lever that runs vertically through the middle of the scale is then rested upon the plate and hooked over the base of the casing.
• 11 The other levers are then hooked over the corners of the case bottom and hooked to the main lever.
• 12 The tooth rack and pinion are then manually connected to two compression springs.
• 13 Next, the metal dial is fixed to the main vertical lever. It rests on the rack and pinion system that will turn the dial based on the person's weight.
• 14 Four brackets that will secure the levers in place are connected to aluminum latches that were molded into the top cover of the scale.
• 15 The two halves of the case are then manually fitted together. The top casing is a little larger than the bottom, but will ensure a snug fit.
• 16 The scale is tested for correct calibration. Then it is packaged and shipped to the distributor.

Quality Control

The parts used to manufacture the scale are checked for defects. Any defective parts that can be salvaged are removed and reused. Parts that are extremely damaged are discarded or recycled. The workers check the calibration of the scale against a known weight before it is packaged. Typically the scale should be able to detect weight within 0.25 lb (0.12 kg).

Byproducts/Waste

Any excess or defective parts are assessed for quality and then either reused or discarded.

The Future

As technology advances, so does the accuracy and application of scales. Today scales can measure not just weight but also body fat. These scales send a mild electrical current through the person's feet and up the rest of the body. The more quickly the signal travels through the body, the less fat. Software is also being developed that allows the scale to keep track of a person's weight loss or gain. Some are even able to track the weights of more than one person. These systems will be able to hook up to software on the home computer to better track weight loss or gain.

Where to Learn More

Other

Bodytrends.Com Web Page. December 2001. <http://www.bodytrends.com>.

ReallyFit.Com Web Page. December 2001.<http://www.reallyfit.com>.

Salter Scales Online. December 2001.<http://www.salterhousewares.com>.

DeirdreS.Blanchfield

Scales

SCALES OF MEASUREMENT

TYPES OF SIMPLE SCALES

COMBINING SCALES INTO INVENTORIES

RELIABILITY AND VALIDITY

BIBLIOGRAPHY

In the social sciences, it is often important to measure attributes of individuals that are not readily observable, such as beliefs, attitudes, emotional experiences, and personality traits. Because such attributes are not readily observable, social scientists rely on scales that allow individuals to report the extent to which they possess or experience them.

SCALES OF MEASUREMENT

A scale provides both qualitative information and quantitative information about an attribute. The most basic type of scale has an individual simply indicate whether he or she possesses a certain attribute. This type of scale provides only a qualitative indication of the presence or absence of the attribute and is considered to have a nominal scale of measurement. A second type of scale has the individual indicate the presence or absence of the attribute in question and the quantitative amount of the attribute he or she possesses. For example, a scale of this sort could ask individuals to indicate how much they like ice cream by selecting a number from one to three, where one represents not at all, two represents moderately, and three represents extremely. This type of a scale has an ordinal scale of measurement, which provides a rank-order quantitative value of the degree to which the attribute is present. Note that even if these values are related to one another in a rank ordering, the psychological distance between neighboring values may not be equivalent (e.g., in the example above, the psychological difference between not at all and moderately may not be the same as the psychological difference between moderately and extremely ). When a scale provides rank-order values of an attribute and equal psychological distances between neighboring values, the scale has an interval scale of measurement. Finally if a scale has equal psychological distances between neighboring values and a value that reflects the complete absence of the attribute in question, then the scale has a ratio scale of measurement. Most scales used by social scientists are nominal or ordinal in nature because it is very difficult to objectively determine if the psychological distance between neighboring scale values is truly equivalent.

TYPES OF SIMPLE SCALES

Two general types of non-nominal scales are used in the social sciences. The first type is the Likert scale, which consists of labeled discrete values located between two labeled endpoint values. The ice cream scale described above is an example of a Likert scale. The second type is the visual analog scale, which consists of either discrete unlabeled values or a continuous unlabeled line between labeled endpoints. Likert scales are ordinal and provide only a limited number of values from which to choose, but they yield information about the qualitative degree to which an individual possesses the attribute in question. In contrast, continuous visual analog scales provide a large number of potential values from which to choose, but they yield little information about the qualitative degree to which an individual possesses the attribute in question. Some believe that visual analog scales have an interval scale of measurement, whereas others argue that they possess only an ordinal scale of measurement.

COMBINING SCALES INTO INVENTORIES

Ratings on individual scales are often combined to form an inventory. Inventories are essential when assessing complex attributes. Creating an inventory ensures that an attribute is measured in its entirety, which may be difficult to accomplish with a single scale. In an inventory, individuals respond to a number of statements using the same scale of measurement. For example, an anger inventory may be created by asking respondents to rate how angry, irritated, and mad they feel, each on a discrete visual analog scale. Each statement in the inventory must refer to a single object in order to minimize confusion. It is also useful to include statements that require responses that are the opposite of other statements in the inventory (e.g., How much do you like ice cream? vs. How much do you hate ice cream?) in order to reduce the likelihood that individuals are reporting responses without paying close attention to the scale items.

RELIABILITY AND VALIDITY

A scale or inventory must be both reliable and valid. Reliability is the extent to which an individual makes similar ratings across time using the same scale or, in the case of an inventory, the similarity of an individual’s responses to related items within the inventory. Assuming that a scale or inventory is reliable, it must also have high construct validity. Construct validity is the extent to which the scale or inventory accurately measures the attribute in question. High construct validity can be demonstrated in a number of ways. First, one can establish convergent validity by showing that responses on the scale or inventory are positively associated with patterns of behavior or responses on another scale or inventory believed to measure the attribute or a similar attribute. Second, one can establish discriminant validity by showing that responses on the scale or inventory are not positively associated with patterns of behavior or responses on another scale or inventory believed to reflect an unrelated attribute.

SEE ALSO Guttman Scale; Likert Scale; Locus of Control; Ordinality; Rotter’s Internal-External Locus of Control Scale; Self-Esteem

BIBLIOGRAPHY

Messick, Samuel. 1995. Validity of Psychological Assessment: Validation of Inferences from Person’s Responses and Performances as Scientific Inquiry into Score Meaning. American Psychologist 50 (9): 741–749.

Robinson, John P., Phillip R. Shaver, and Lawrence S. Wrightsman. 1991. Measures of Personality and Social Psychological Attitudes. San Diego, CA: Academic Press.

David A. Lishner

E. L. Stocks

scale (from It. scala, ‘staircase’, ‘ladder'; Ger. Tonleiter; Fr. gamme). A series of single notes progressing up or down stepwise. Thus, a series of notes within an octave used as the basis of comp. Scales are arbitrary, and the no. in use throughout the world is incalculable.

For the older European scales, used in the Church's plainsong and in folk song, see modes. Two of these ancient modes remained in use by composers, when the other 10 were almost abandoned, and these are our major and minor scales—the latter, however, subject to some variations in its 6th and 7th notes. Taking C as the keynote these scales (which have provided the chief material of music from about AD 1600 to 1900) run as follows:



The major and minor scales are spoken of as DIATONIC SCALES, as distinct from a scale using nothing but semitones, which is the CHROMATIC SCALE, for which 2 different notations are employed:

This scale when begun on other notes is ‘harmonically’ notated according to the same principles; for instance, beginning on D it reads:

A scale comprising the same notes as the chromatic scale is the DODECAPHONIC SCALE, in which the 12 notes are considered to be all of equal status and are so treated, whereas the chromatic scale beginning on any particular note is considered to comprise the diatonic scale of that note ‘coloured’ (this is the literal meaning of ‘chromatic’) by the addition of the extra semitones.

Scales with smaller intervals than the semitone have been introduced. See microtone.

The WHOLE-TONE SCALE is free of semitones and thus allows of only 2 different series, each with 6 notes:



An extremely widespread scale is the 5-note or PENTATONIC SCALE (common in Scottish, Chinese, and other music):

The Scottish Highland Bagpipe is tuned to a scale that cannot be represented in orthodox notation. It is roughly that of the white notes of the piano with the C and F about a quarter of a tone sharp.

scales, scaling A form of measurement technique based on the observation of supposed common cultural meanings or shared social interpretations. One common sociological use of this technique is the attempt to devise measures of social prestige or social standing via occupational scaling—as, for example, in the Hope-Goldthorpe scale of occupational prestige (see J. H. Goldthorpe and and K. Hope . The Social Grading of Occupations, 1974
). However, the most frequent application of scaling techniques in sociology is probably in the measurement of attitudes and personality traits, in which field a number of specialist scaling techniques have been devised. See also AUTHORITARIAN PERSONALITY; BOGARDUS SOCIAL DISTANCE SCALE; EQUAL APPEARING INTERVALS; GUTTMAN SCALE; LIKERT SCALE; MULTI-DIMENSIONAL SCALING; SEMANTIC DIFFERENTIAL.