balance

Bal·ance

B0035600 (băl′əns)n. See Libra.

bal·ance

B0035600 (băl′əns)n.1. A weighing device, especially one consisting of a rigid beam horizontally suspended by a low-friction support at its center, with identical weighing pans hung at either end, one of which holds an unknown weight while the effective weight in the other is increased by known amounts until the beam is level and motionless. Also called scale.2. A state of equilibrium or parity characterized by cancellation of all forces by equal opposing forces.3. The power or means to decide: matters that fell outside the judge's balance.4. a. A state of bodily equilibrium: thrown off balance by a gust of wind.b. The ability to maintain bodily equilibrium: Gymnasts must have good balance.5. A harmonious or satisfying arrangement or proportion of parts or elements, as in a design.6. An influence or force tending to produce equilibrium; counterpoise.7. The difference in magnitude between opposing forces or influences.8. Accounting a. Equality of totals in the debit and credit sides of an account.b. The difference between such totals, either on the credit or the debit side.9. Something that is left over; a remainder.10. Chemistry Equality of mass and net electric charge of reacting species on each side of an equation.11. Mathematics Equality with respect to the net number of reduced symbolic quantities on each side of an equation.12. A balance wheel.v. bal·anced, bal·anc·ing, bal·anc·es v.tr.1. To determine the weight of (something) in a weighing device.2. To consider and compare or assess: balanced the pros and cons before making a choice.3. To bring into or maintain in a state of equilibrium.4. To act as an equalizing weight or force to; counterbalance.5. Accounting a. To compute the difference between the debits and credits of (an account).b. To reconcile or equalize the sums of the debits and credits of (an account).c. To settle (an account, for example) by paying what is owed.6. To bring into or keep in equal or satisfying proportion or harmony.7. Mathematics & Chemistry To bring (an equation) into balance.8. To move toward and then away from (a dance partner).v.intr.1. To be in or come into equilibrium.2. To be equal or equivalent.3. To sway or waver as if losing or regaining equilibrium.4. To move toward and then away from a dance partner.Idioms: in the balance In an undetermined and often critical position: Our plans were left hanging in the balance. Resolution of that item is still in the balance. on balance Taking everything into consideration; all in all.

[Middle English balaunce, from Old French, from Vulgar Latin *bilancia, having two scale pans, from Latin bilānx : bi-, two; see dwo- in Indo-European roots + lānx, scale.]

bal′ance·a·ble adj.

balance

(ˈbæləns) n1. (General Physics) a weighing device, generally consisting of a horizontal beam pivoted at its centre, from the ends of which two pans are suspended. The substance to be weighed is placed in one pan and known weights are placed in the other until the beam returns to the horizontal. See also microbalance2. an imagined device for assessing events, actions, motives, etc, in relation to each other (esp in the phrases weigh in the balance, hang in the balance)3. a state of equilibrium4. something that brings about such a state5. equilibrium of the body; steadiness: to lose one's balance. 6. (Psychology) emotional stability; calmness of mind7. (Art Terms) harmony in the parts of a whole: balance in an artistic composition. 8. the act of weighing factors, quantities, etc, against each other9. the power to influence or control: he held the balance of power. 10. (Accounting & Book-keeping) something that remains or is left: let me have the balance of what you owe me. 11. (Accounting & Book-keeping) accounting a. equality of debit and credit totals in an accountb. a difference between such totals12. (Chemistry) chem the state of a chemical equation in which the number, kind, electrical charges, etc, of the atoms on opposite sides are equal13. a balancing movement14. (General Physics) short for spring balance15. in the balance in an uncertain or undecided condition16. on balance after weighing up all the factors17. strike a balance to make a compromisevb18. (tr) to weigh in or as if in a balance19. (intr) to be or come into equilibrium20. (tr) to bring into or hold in equilibrium21. (tr) to assess or compare the relative weight, importance, etc, of22. (tr) to act so as to equalize; be equal to23. (tr) to compose or arrange so as to create a state of harmony24. (Chemistry) (tr) to bring (a chemical or mathematical equation) into balance25. (Accounting & Book-keeping) (tr) accounting a. to compute the credit and debit totals of (an account) in order to determine the differenceb. to equalize the credit and debit totals of (an account) by making certain entriesc. to settle or adjust (an account) by paying any money due26. (Accounting & Book-keeping) (intr) (of a business account, balance sheet, etc) to have the debit and credit totals equal27. (Dancing) to match or counter (one's dancing partner or his or her steps) by moving towards and away from him or her[C13: from Old French, from Vulgar Latin bilancia (unattested), from Late Latin bilanx having two scalepans, from bi-¹ + lanx scale] ˈbalanceable adj

Balance

(ˈbæləns) n (Astrology) the Balance the constellation Libra, the seventh sign of the zodiac

bal•ance

(ˈbæl əns)

n., v. -anced, -anc•ing. n. 1. a state of equilibrium or equipoise; equal distribution of weight, amount, etc. 2. something used to produce equilibrium; counterpoise. 3. the ability to maintain bodily equilibrium. 4. mental or emotional steadiness. 5. an instrument for determining weight, typically by the equilibrium of a bar, from each end of which is suspended a scale or pan. 6. the remainder or rest. 7. the power or ability to decide an outcome. 8. a. equality between the totals of the two sides of an account. b. the difference between the debit total and the credit total of an account. c. unpaid difference represented by the excess of debits over credits. 9. preponderant weight: The balance of the blame is on your side. 10. the harmonious integration of components in an artistic work. 11. a wheel that oscillates against the tension of a hairspring to regulate the beats of a watch or clock. 12. (cap.) Libra. 13. (in a stereophonic sound system) the comparative loudness of two speakers. v.t. 14. to bring to or hold in equilibrium; poise: to balance a book on one's head. 15. to arrange or adjust the parts of symmetrically. 16. to be equal or proportionate to. 17. to add up the two sides of (an account) and determine the difference. 18. to weighin a balance. 19. to estimate the relative weight or importance of. 20. to serve as a counterpoise to. v.i. 21. to have an equality or equivalence; be in equilibrium. 22. to be in a state wherein debits equal credits. Idioms: 1. in the balance, with the outcome in doubt or suspense. 2. on balance, considering all aspects. [1250–1300; < Anglo-French; Old French < Vulgar Latin *balancia, for *bilancia < Late Latin bilanx with double scales < Latin bi- bi-¹ + lanx metal dish] bal′ance•a•ble, adj. syn: See symmetry.

bal·ance

(băl′əns) To adjust a chemical equation so that the number of each type of atom, and the total charge, on the reactant (left-hand) side of the equation matches the number and charge on the product (right-hand) side of the equation.

balance

A concept as applied to an arms control measure that connotes: a. adjustments of armed forces and armaments in such a manner that one state does not obtain military advantage over other states agreeing to the measure; and b. internal adjustments by one state of its forces in such manner as to enable it to cope with all aspects of remaining threats to its security in a post arms control agreement era.

balance

Past participle: balanced
Gerund: balancing

Imperative
balance
balance

Present
I balance
you balance
he/she/it balances
we balance
you balance
they balance

Preterite
I balanced
you balanced
he/she/it balanced
we balanced
you balanced
they balanced

Present Continuous
I am balancing
you are balancing
he/she/it is balancing
we are balancing
you are balancing
they are balancing

Present Perfect
I have balanced
you have balanced
he/she/it has balanced
we have balanced
you have balanced
they have balanced

Past Continuous
I was balancing
you were balancing
he/she/it was balancing
we were balancing
you were balancing
they were balancing

Past Perfect
I had balanced
you had balanced
he/she/it had balanced
we had balanced
you had balanced
they had balanced

Future
I will balance
you will balance
he/she/it will balance
we will balance
you will balance
they will balance

Future Perfect
I will have balanced
you will have balanced
he/she/it will have balanced
we will have balanced
you will have balanced
they will have balanced

Future Continuous
I will be balancing
you will be balancing
he/she/it will be balancing
we will be balancing
you will be balancing
they will be balancing

Present Perfect Continuous
I have been balancing
you have been balancing
he/she/it has been balancing
we have been balancing
you have been balancing
they have been balancing

Future Perfect Continuous
I will have been balancing
you will have been balancing
he/she/it will have been balancing
we will have been balancing
you will have been balancing
they will have been balancing

Past Perfect Continuous
I had been balancing
you had been balancing
he/she/it had been balancing
we had been balancing
you had been balancing
they had been balancing

Conditional
I would balance
you would balance
he/she/it would balance
we would balance
you would balance
they would balance

Past Conditional
I would have balanced
you would have balanced
he/she/it would have balanced
we would have balanced
you would have balanced
they would have balanced

Thesaurus

Noun	1.	balance - a state of equilibrium equilibrium - a stable situation in which forces cancel one anothertension - a balance between and interplay of opposing elements or tendencies (especially in art or literature); "there is a tension created between narrative time and movie time"; "there is a tension between these approaches to understanding history"electrolyte balance - an equilibrium between the amounts of electrolytes (as calcium and sodium and potassium) that is essential for normal health and functioningnitrogen balance - the balance between the amount of nitrogen taken in (to the soil or the body) and the amount given off (lost or excreted)imbalance, unbalance, instability - a lack of balance or state of disequilibrium; "a hormonal imbalance"
	2.	balance - equality between the totals of the credit and debit sides of an accountequality - the quality of being the same in quantity or measure or value or statusaccount statement, accounting, account - a statement of recent transactions and the resulting balance; "they send me an accounting every month"trial balance - a balance of debits and credits in double-entry bookkeeping; drawn up to test their equality
	3.	balance - harmonious arrangement or relation of parts or elements within a whole (as in a design); "in all perfectly beautiful objects there is found the opposition of one part to another and a reciprocal balance"- John Ruskinproportionality, proportionplacement, arrangement - the spatial property of the way in which something is placed; "the arrangement of the furniture"; "the placement of the chairs"
	4.	balance - equality of distribution equipoise, counterbalance, equilibriumstructure, construction - a thing constructed; a complex entity constructed of many parts; "the structure consisted of a series of arches"; "she wore her hair in an amazing construction of whirls and ribbons"conformation - a symmetrical arrangement of the parts of a thingsymmetry, proportion - balance among the parts of something
	5.	balance - something left after other parts have been taken away; "there was no remainder"; "he threw away the rest"; "he took what he wanted and I got the balance"remainder, residual, residuum, rest, residuecomponent part, part, portion, component, constituent - something determined in relation to something that includes it; "he wanted to feel a part of something bigger than himself"; "I read a portion of the manuscript"; "the smaller component is hard to reach"; "the animal constituent of plankton"leftover, remnant - a small part or portion that remains after the main part no longer exists
	6.	balance - the difference between the totals of the credit and debit sides of an accountbalance of trade, trade balance, trade gap, visible balance - the difference in value over a period of time of a country's imports and exports of merchandise; "a nation's balance of trade is favorable when its exports exceed its imports"carry-forward, carry-over - the accumulated and undivided profits of a corporation after provision has been made for dividends and reservescompensating balance, offsetting balance - a minimum credit balance that a bank may require a borrower to keep on deposit as a condition for granting a loan; a common requirement for establishing a line of credit at a bank; "the compensating balance increases the effective interest rate to the bank since the net amount loaned is reduced but the interest paid is unchanged"invisible balance - the difference in value over a period of time of a country's imports and exports of services and payments of property incomesremainder, difference - the number that remains after subtraction; the number that when added to the subtrahend gives the minuend
	7.	Balance - (astrology) a person who is born while the sun is in LibraLibraindividual, mortal, person, somebody, someone, soul - a human being; "there was too much for one person to do"astrology, star divination - a pseudoscience claiming divination by the positions of the planets and sun and moon
	8.	Balance - the seventh sign of the zodiac; the sun is in this sign from about September 23 to October 22Libra the Balance, Libra the Scales, Libra
	9.	balance - (mathematics) an attribute of a shape or relation; exact reflection of form on opposite sides of a dividing line or planesymmetricalness, symmetry, correspondencespatial property, spatiality - any property relating to or occupying spacegeometrical regularity, regularity - a property of polygons: the property of having equal sides and equal anglesbilateral symmetry, bilateralism, bilaterality - the property of being symmetrical about a vertical planeradial symmetry - the property of symmetry about an axis; "the starfish illustrates radial symmetry"math, mathematics, maths - a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement
	10.	balance - a weight that balances another weightcounterbalance, counterpoise, counterweight, equaliser, equalizersash weight - a counterweight for a sliding sashtare - (chemical analysis) a counterweight used in chemical analysis; consists of an empty container that counterbalances the weight of the container holding chemicalsweight - an artifact that is heavy
	11.	balance - a wheel that regulates the rate of movement in a machine; especially a wheel oscillating against the hairspring of a timepiece to regulate its beatbalance wheelhorologe, timepiece, timekeeper - a measuring instrument or device for keeping timewheel - a simple machine consisting of a circular frame with spokes (or a solid disc) that can rotate on a shaft or axle (as in vehicles or other machines)
	12.	balance - a scale for weighing; depends on pull of gravitybeam balance - a balance consisting of a lever with two equal arms and a pan suspended from each armelectronic balance - a balance that generates a current proportional to the displacement of the panmicrobalance - balance for weighing very small objectsweighing machine, scale - a measuring instrument for weighing; shows amount of massspring balance, spring scale - a balance that measure weight by the tension on a helical springbeam scale, lever scale, steelyard - a portable balance consisting of a pivoted bar with arms of unequal length
Verb	1.	balance - bring into balance or equilibrium; "She has to balance work and her domestic duties"; "balance the two weights"equilibrise, equilibrize, equilibratecomplement - make complete or perfect; supply what is wanting or form the complement to; "I need some pepper to complement the sweet touch in the soup"match, fit - make correspond or harmonize; "Match my sweater"balance, poise - hold or carry in equilibriumcounterbalance, even off, even out, even up, compensate, correct, make up - adjust for; "engineers will work to correct the effects or air resistance"cancel, offset, set off - make up for; "His skills offset his opponent's superior strength"countervail, offset - compensate for or counterbalance; "offset deposits and withdrawals"balance - be in equilibrium; "He was balancing on one foot"trim - balance in flight by regulating the control surfaces; "trim an airplane"unbalance - throw out of balance or equilibrium; "The tax relief unbalanced the budget"; "The prima donna unbalances the smooth work in our department"
	2.	balance - compute credits and debits of an accountaccount, calculate - keep an account of
	3.	balance - hold or carry in equilibriumpoisecarry, bear, hold - support or hold in a certain manner; "She holds her head high"; "He carried himself upright"juggle - hold with difficulty and balance insecurely; "the player juggled the ball"balance, equilibrise, equilibrize, equilibrate - bring into balance or equilibrium; "She has to balance work and her domestic duties"; "balance the two weights"
	4.	balance - be in equilibrium; "He was balancing on one foot"be - have the quality of being; (copula, used with an adjective or a predicate noun); "John is rich"; "This is not a good answer"balance, equilibrise, equilibrize, equilibrate - bring into balance or equilibrium; "She has to balance work and her domestic duties"; "balance the two weights"

balance

verb1. stabilize, support, level, steady He balanced a football on his head.
stabilize upset, outweigh, overbalance2. offset, match, square, make up for, compensate for, counteract, neutralize, counterbalance, even up, equalize, counterpoise Balance spicy dishes with mild ones.3. weigh, consider, compare, estimate, contrast, assess, evaluate, set against, juxtapose She carefully tried to balance religious sensitivities against democratic freedom.4. (Accounting) calculate, rate, judge, total, determine, estimate, settle, count, square, reckon, work out, compute, gauge, tally He balanced his budget by rigid control over public expenditure.noun1. equilibrium, stability, steadiness, evenness, equipoise, counterpoise The medicines you are currently taking could be affecting your balance.
equilibrium instability, unbalance, disproportion2. stability, equanimity, constancy, steadiness the ecological balance of the forest3. parity, equity, fairness, impartiality, equality, correspondence, equivalence her ability to maintain the political balance4. remainder, rest, difference, surplus, residue, outstanding amount They were due to pay the balance on the delivery.5. composure, stability, restraint, self-control, poise, self-discipline, coolness, calmness, equanimity, self-restraint, steadiness, self-possession, self-mastery, strength of mind or will a balance of mind

balance

noun1. A stable state characterized by the cancellation of all forces by equal opposing forces:counterpoise, equilibrium, equipoise, stasis.2. A stable, calm state of the emotions:aplomb, collectedness, composure, coolness, equanimity, imperturbability, imperturbableness, nonchalance, poise, sang-froid, self-possession, unflappability.Slang: cool.3. Satisfying arrangement marked by even distribution of elements, as in a design:harmony, proportion, symmetry.4. What remains after a part has been used or subtracted:leavings, leftover, remainder, remains, remnant, residue, rest.verb1. To examine in order to note the similarities and differences of:collate, compare.2. To put in balance:counterbalance, equalize, stabilize, steady.3. To act as an equalizing weight or force to:compensate, counteract, counterbalance, counterpoise, countervail, make up, offset, set off.4. To make up for:compensate, counterbalance, counterpoise, countervail, neutralize, offset, outweigh, redeem, set off.5. To place or be placed on a narrow or insecure surface:perch, poise.

Translations

平衡收支差额收支平衡稳定天平

balance

(ˈbӕləns) noun1. a weighing instrument. 天平2. a state of physical steadiness. The child was walking along the wall when he lost his balance and fell.平衡3. state of mental or emotional steadiness. The balance of her mind was disturbed.稳定4. the amount by which the two sides of a financial account (money spent and money received) differ. I have a balance (= amount remaining) of $100 in my bank account; a large bank balance.收支差额 verb1. (of two sides of a financial account) to make or be equal. I can't get these accounts to balance.收支平衡2. to make or keep steady. She balanced the jug of water on her head; The girl balanced on her toes.平衡balance sheet a paper showing a summary and balance of financial accounts. 帐目收支表in the balance in an undecided or uncertain state. Her fate is (hanging) in the balance.悬而未决off balance not steady. He hit me while I was off balance.失去平稳on balance having taken everything into consideration. On balance I think Miss Smith is a better tennis player than my sister.总的说来

balance

→ 平衡zhCN

balance

balance,

instrument used in laboratories and pharmacies to measure the mass or weight of a body. A balance functions by measuring the force of gravity that the earth exerts on an object, i.e., its weight. Since the mass of an object is directly proportional to its weight, a balance can also be used to measure mass.

Types of Balances

The Equal-Arm Balance

The simplest type of balance, the equal-arm, or beam, balance, is an application of a leverlever,
simple machine consisting of a bar supported at some stationary point along its length and used to overcome resistance at a second point by application of force at a third point. The stationary point of a lever is known as its fulcrum.
..... Click the link for more information. . A uniform bar, the beam, is suspended at its exact center on a knife-edge set at right angles to it. The point of support is called the fulcrum. Two pans of equal weight are suspended from the beam, one at each end, at points equidistant from the fulcrum. Since the center of gravity of a uniform bar is at its midpoint, the beam supporting the pans will be in equilibrium, i.e., will balance on the knife-edge. A long pointer attached at right angles to the beam at the fulcrum indicates zero on a scale when the beam is at rest parallel to a level surface. It shows also the extent of swing of the beam on one side or the other, acting somewhat as a pendulum, when the beam is coming to rest. The object to be weighed is placed on one pan, and standard weights are added to the other until the balance of the beam is established again. The unknown weight can then be determined by adding up the standard weights in the pan.

The platform balance is a form of equal-arm balance in which two flat platforms are attached to the top side of the beam, one at each end. Such a balance has a rider, or weight, mounted on a bar that has a calibrated scale, is parallel to the beam, and connects the supports of the two platforms. This rider is moved along the bar, its edge marking decimal fractions of the unit weight.

The Unequal-Arm Balance

On the unequal-arm balance the beam is suspended at a point a very short distance from one of its ends. The object to be weighed is placed on this end, and a small known weight is moved out along the longer arm until balance is obtained. The unknown weight is then determined by using a formula involving the known weight and the distance of each weight from the fulcrum. One example of this type of balance is the steelyard, an ancient device still used in underdeveloped nations because of its portability and low cost; since the difference in length of the arms can multiply the effect of the smaller weight by a factor of 100 or more, a small steelyard hung from a tree can be used, for example, to weigh a side of beef.

The Spring Balance

A spring balance consists of a coiled spring fixed to a support at one end, with a hook at the other to which the body to be weighed is applied. Within the spring's limit of elasticity, the distance through which it is stretched is directly proportional to the weight of the applied body. A pointer and graduated scale attached to the spring convert this distance into a weight reading.

Accuracy of Balances

Although extremely accurate results can be obtained in measuring the weights of minute objects, it is physically impossible to construct any balance perfect enough to yield absolutely accurate determinations. For example, the analytical balance, a type of equal-arm balance, is used for delicate weighing in quantitative chemical analysis and in preparing pharmaceutical prescriptions; it must be kept in a glass case, since its accuracy is easily affected by dust and moisture. A spring balance does not retain its accuracy permanently, for no matter how carefully it is handled, the spring very gradually uncoils even though its limit of elasticity has not been exceeded.

For ordinary purposes the errors are so small that they are considered insignificant, but in chemical analysis it has been necessary to develop methods by which they can be further minimized. A so-called torsion balancetorsion balance,
instrument used to measure small forces. It is based on the principle that a wire or thread resists twisting with a force that is proportional to the stress.
..... Click the link for more information. , which depends on the twisting of a wire or thread, is employed for weighing, but the term is commonly used to indicate a device for measuring minute electrical and magnetic forces.

See scalescale,
in weights and measures, instruments for determining weight, generally for other than laboratory use. For the principles of operation of all weighing devices, see balance.
..... Click the link for more information. .

Balance

A harmonizing or satisfying arrangement, or proportion of various parts, as in a design or composition; the state of equipoise between different architectural elements.

formal balance

Designs that are almost always characterized by symmetrical elements.

informal balance

Designs where the forms are mostly asymmetrical.

Balance

(scales), an instrument for determining the weight of an object by the gravitational force acting upon it. Instruments for measuring other physical quantities, which are converted for this purpose to forces or force moments are sometimes called balances—for example, the electrodynamic balance and Coulomb’s balance.

The balance is one of the oldest of instruments. It originated and was perfected in connection with the development of trade, manufacturing, and science. The simplest balance, in the form of an equal-armed beam with suspended pans, was widely used in barter in ancient Babylon (2500 B.C.) and Egypt (2000 B.C.). The unequal-armed balance with a movable weight appeared somewhat later. As early as the fourth century B.C., Aristotle stated the theory of such balances (the rule of force moments). In the 12th century the Arab scholar Alhazen described a balance with scale pans whose error did not exceed 0.1 percent. It was used for determining the density of various substances, which made it possible to recognize alloys, expose counterfeit coins, distinguish precious stones from imitation stones, and so on. In 1586, Galileo constructed a special hydrostatic balance for determining the density of bodies. The general theory of the balance was developed by L. Euler in 1747.

The development of industry and transport led to the invention of balances for large loads. At the beginning of the 19th century a decimal balance with a weight-to-load ratio of 1:10 (Quintenz, 1818; see Figure 1) and a centesimal balance (T. Fairbanks, 1831) were built. At the turn of the 20th century, with the development of flow production, balances appeared for continuous weighing—conveyor balances, metering balances, and so on. Balances of the most varied construction began to be used in agriculture, industry, and in transportation for weighing solid products—in agriculture, grains, root crops, and eggs; in transportation, automobiles, railroad cars, and airplanes; and in industry, the tiniest components and units of precision-instrument manufacture and the multiton ingots of metallurgy. The construction of precision balances—the analytic balance, microanalytic balance,

Figure 1. Diagram of a decimal balance of the Quintenz system: AOK is a lever of the first order and EDC is a lever of the second order. The weights equilibrate a tenfold load under the following condition: OA: OB=10:1; CE:CD=OK:OB.

Balances are classified according to purpose as standard balances (for checking balance weights), laboratory balances (including analytical balances), and general-purpose balances (used in various fields of science, technology, and the national economy). According to principle of operation, balances are divided into beam, spring, electrotensometric, hydrostatic, and hydraulic.

The most widely used balance is the beam balance. Its operation is based on the law of equilibrium of the lever. The fulcrum of the lever (the beam of the balance) may be in the middle (equal-armed balance) or shifted in relation to the middle (unequal-armed or one-armed balances). Many beam balances—for example, mercantile, automobile, and portion balances—consist of a combination of levers of the first and second orders. Knife edges or cushions of special steels or of hard stone (agate or corundum) usually serve as supports for the levers. On an equal-armed beam balance the object to be weighed is balanced by weights, but a certain excess (usually 0.05-0.1 percent) of the weights over the object (or vice versa) is compensated by the moment produced by the beam (with a pointer) because of displacement of its center of gravity relative to the initial position. The load, compensated by displacement of the beam’s center of gravity, is measured on a graduated scale. The value of a division s on the scale of a beam balance is determined by the formula

s = k (P₀c/lg)

where P₀ is the weight of the beam and its pointer, c is the distance between the beam’s center of gravity and the axis of its rotation, l is the length of the beam arm, g is free-fall acceleration, and k is a coefficient that is a function only of the resolving power of the reading device. The value of the division, and consequently the sensitivity of the balance as well, may be changed within definite limits (usually by moving a special small weight that changes the distance c).

In a number of laboratory beam balances a portion of the measured load is compensated by the force of electromagnetic interaction—by the attraction toward an immovable solenoid of an iron core connected to the arm of the beam. The strength of the current in the solenoid is regulated by an electronic device that brings the balance to equilibrium. By measuring the strength of the current, the load—which is proportional to it—can be determined. A similar type of balance is automatically brought to a position of equilibrium and is therefore generally used for measuring changing mass (for example, in research on processes of oxidation and condensation) when it is inconvenient or impossible to use an ordinary balance. The center of gravity of the beam in these balances coincides with the axis of rotation.

Balances, especially analytical balances, with built-in weights on a part of the load or on the whole load are coming into wider use in laboratory practice. The principle of operation of such balances was proposed by D. I. Mendeleev. Specially formed balance weights are suspended from the arm that has the balance pan (one-armed balance) or, less frequently, from the opposite arm. In one-armed balances (Figure 2), error caused by the inequality of the beam arms is completely eliminated.

Figure 2. Diagram of a one-armed analytic balance: (1) beam, (2) built-in weights, (3) balance pan, (4) counterweight and damper, (5) light source, (6) projection scale, (7) lens, (8) device for zero correction, (9) screen.

Modern laboratory balances (analytical and other types) are equipped with a number of devices to increase the precision and speed of weighing—pneumatic or magnetic pan oscillation dampers, doors whose opening causes almost no air currents, heat shields, mechanisms for applying and removing the built-in balance weights, and automatic mechanisms for selection of built-in weights when equilibrating the balance. Projection scales that permit widening the range of measurements on the reading scale with small angles of deviation of the beam are used more and more frequently. All this makes it possible to significantly increase the speed of operation of the balance while preserving its precision.

In high-speed technical quadrant balances (Figure 3) the limit of measurements on the scale of the deviation of the beam is 50-100 percent of the maximum load of the balance (usually between 20 g and 10 kg). This is achieved by special construction of a heavy beam (quadrant) whose center of gravity is considerably lower than its axis of rotation.

Figure 3. Quadrant balance with projection scale: (1) balance pan, (2) counterweight-quadrant, (3) lever whose angle of deviation is measured on the projection scale (4), through which a light beam (5) passes, which projects the image of the scale on the screen (6).

Most types of metrological, standard, analytical, technical, mercantile, medical, wagon, and automobile balances—and also most automatic and portion balances—are built according to the principle of the beam balance.

The basis for the operation of spring and electrotensometric balances is Hooke’s law.

The sensitive element of the spring balance is a flat or cylindrical spiral spring that is deformed under the action of the weight of the body. The readings of the balance are shown on the scale, along which an indicator that is connected to the spring moves. It is assumed that the indicator will return to zero position after the load is removed; no residual deformation of the spring will occur because of the load.

Weight, rather than mass, is measured by the spring balance; however, in the majority of cases, the scale of the spring balance is graduated in units of mass. Since free-fall acceleration is a function of geographic latitude and altitude above sea level, the readings of the spring balance depend on its location. Moreover, the elastic properties of the spring depend on temperature and change with time; all this decreases the accuracy of spring balances.

In the torsion balance an elastic filament or spiral springs serve as the sensitive element. The load is determined by the angle of twist of the spring filament, which is proportional to the torsion moment produced by the load.

The operation of the electrotensometric balance is based on the conversion of the deformation of the resilient elements (columns, plates, or rings), which sense the force effects of the load, into a change in electrical resistance. Highly sensitive wire tensometers attached to the resilient elements serve as converters. As a rule, electrotensometric balances (wagon, automobile, crane, and other types) are used for weighing large loads.

Hydrostatic balances are used mainly to determine the densities of solid bodies and fluids. Their operation is based on Archimedes’ principle.

The hydraulic balance is analogous in arrangement to the hydraulic press. The results are read on a manometer graduated in units of mass.

All types of balances are characterized by (1) maximum load—the heaviest static load that they can tolerate without disruption of their metrological characteristics; (2) value of a scale division—the mass that corresponds to a change of one scale division in the reading; (3) maximum permissible error in weighing—the largest permissible difference between the result of one weighing and the actual weight of the weighed object; and (4) permissible reading variation—the greatest permissible difference in the readings of repeated weighings of the same body.

The weighing errors with maximum load of several types of balances are shown in Table 1.

Table 1. Characteristics of various types of balances
¹Using precision weighing methods
	Maximum load	Weighing error with maximum load
Metrological...............	1 kg	0.005mg¹
Standard, first and second class...............	1-20kg	0.5-20mg¹
	2-200g	0.01-1.0mg¹
Standard, third class; technical, first class...............	1-20kg	20-100mg
	2-200g	0.4-10mg
Analytic, semimicroanalytic, microanalytic, and assay...............	200g	0.1-1.0mg¹
	100g	0.1-1.0mg¹
	20g	0.01-0.1mg¹
	2g	0.004-0.02mg¹
	1g	0.004-0.01mg¹
Medical...............	150kg	50g
	20g	10g
Household...............	2-30kg	5-60g
Automobile...............	10-50tons	10-50kg
Wagon...............	50-150tons	50-150kg
Torsion...............	20-1,000mg	0.05-1.0mg
	0.5-5mg	0.001-0.1mg

REFERENCES

Rudo, N. M. Vesy: Teoriia, ustroistvo, regulirovka i poverka. Moscow-Leningrad, 1957.
Malikov, L. M., and N. A. Smirnova. “Analiticheskie elektricheskie vesy.” In Entsiklopediia izmerenii kontrolia i avtomatizatsii, issue 1. Moscow-Leningrad, 1962.
Orlov, S. P., and Avdeev, B. A. Vesovoe oborudovanie predpriiatii. Moscow, 1962.
Karpin, E. B. Raschet i konstruirovanie vesoizmeritel’nykh mekhanizmov i dozatorov. Moscow, 1963.
Gauzner, S. I., S. S. Mikhailovskii, and V. V. Orlov. Registriruiushchie ustroistva v avtomaticheskikh protsessakh vzveshivaniia. Moscow, 1966.

N. A. SMIRNOVA

Balance

(1) In bookkeeping, the difference between the totals for the debit and credit entries of an account. A debit balance, in which debits exceed credits, reflects the state of the given type of economic asset as of a certain date and is shown in the assets of the balance sheet. A credit balance, in which credits exceed debits, reflects the state of the sources of economic assets and is shown in the liabilities. The account is said to be closed if there is no balance.

(2) In foreign trade relations, the balance is the difference between the totals for exports and imports or between the totals for demands and obligations. An excess of exports over imports produces a positive foreign trade balance, whereas an excess of imports over exports produces a negative balance. In the balance of payments, a positive balance indicates that a country’s total receipts from other countries exceed the country’s payments to other countries. In a negative balance of payments, a country’s payments to other countries exceed a country’s receipts from other countries.

balance

[′bal·əns] (acoustics) The condition in a stereo system wherein both speakers produce the same average sound levels. (aerospace engineering) The equilibrium attained by an aircraft, rocket, or the like when forces and moments are acting upon it so as to produce steady flight, especially without rotation about its axes. The equilibrium about any specified axis that counterbalances something, especially on an aircraft control surface, such as a weight installed forward of the hinge axis to counterbalance the surface aft of the hinge axis. (chemistry) To bring a chemical equation into balance so that reaction substances and reaction products obey the laws of conservation of mass and charge. (electricity) The state of an electrical network when it is adjusted so that voltage in one branch induces or causes no current in another branch. (engineering) An instrument for measuring mass or weight. (mining engineering) The counterpoise or weight attached by cable to the drum of a winding engine to balance the weight of the cage and hoisting cable and thus assist the engine in lifting the load out of the shaft.

Balance

[′bal·əns] (astronomy) Libra

balance

1. a weighing device, generally consisting of a horizontal beam pivoted at its centre, from the ends of which two pans are suspended. The substance to be weighed is placed in one pan and known weights are placed in the other until the beam returns to the horizontal 2. Chem the state of a chemical equation in which the number, kind, electrical charges, etc., of the atoms on opposite sides are equal 3. short for spring balance

balance

Bal·ance

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balance,

Types of Balances

The Equal-Arm Balance

The Unequal-Arm Balance

The Spring Balance

Accuracy of Balances

Balance

formal balance

informal balance

Balance

REFERENCES

Balance

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Patient discussion about balance

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Account Balance

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balance

Synonyms for balance

verb stabilize

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Antonyms

verb offset

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verb weigh

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verb calculate

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noun equilibrium

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Antonyms

noun stability

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noun parity

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noun remainder

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noun composure

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Synonyms for balance

noun a stable state characterized by the cancellation of all forces by equal opposing forces

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noun a stable, calm state of the emotions

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noun satisfying arrangement marked by even distribution of elements, as in a design

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noun what remains after a part has been used or subtracted

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verb to examine in order to note the similarities and differences of

Synonyms

verb to put in balance

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verb to act as an equalizing weight or force to