THULABHARAM 3 Continuing fromPart 2 Re- posted after editing and updatinginformation.
Gopalakrishnan dated 7-10-21 13. Whether weighing scale or weighinginstrument? Aweighing scale (usually just "scales" in UK and Australian English,"weighing machine" in south Asian English or "scale" in USEnglish) is a measuring instrument for determining the weight or mass of anobject. 14 Difference between mass and weight? Justto understand weight is attraction towards earth of an object. I have read thata man would fly inMoon’s atmosphere because pulling force or compression force is very less foran object towards it. A spring scale measures weight by the distance a springdeflects under its load. Anarm balance compares the torque on the arm due to the sample weight to thetorque on the arm due to a standard reference weight using a horizontal lever. Balances are different from scales, in thata balance measures mass (or more specifically gravitational mass), where as a scale measures weight (or morespecifically, either the tension or compression force of constraint provided bythe scale). Thoughstudied in high school, the difference between mass and weight became very clear only when studiedin college. Aeroplane loaded with luggage and passengers would weigh comparativelyless in high altitude while it moves. 15. How much we can weigh usingbalance/ scale Weighingscales are used in many industrial and commercial applications, and productsfrom FEATHERS TO LOADED TRACTOR-TRAILERS are weighed. Specializedmedical scales and bathroom scales are used to measure the body weight of humanbeings. Iam not sure why the scale used to weigh our weight standing on it is calledBATH ROOM SCALE. Probably in many countries the scale would have it’s place inBath rooms. 16. History of balance Thebalance scale is such a simple device that its usage likely far predates theevidence. What has allowed archaeologists to link arti- facts to weighingscales are the stones for determining absolute weight. The balance scale itselfwas probably used to determine RELATIVE WEIGHT LONG BEFORE ABSOLUTE WEIGHT. Relativeweight means simply which is more weighing. One bottle of Kerosene would weigh less than water in an identical bottle which explainsrelative weight. If the water weighed 1 kg, kerosene would weigh only 800 gramsper litre. Theoldest evidence for the existence of weighing scales dates to c. 2400-1800 B.C.E. in the INDUSRIVER VALLEY. Uniform, polished stone cubes discovered in earlysettlements were probably used as weight-setting stones in balance scales. Althoughthe cubes bore no markings, their weights are multiples of a commondenominator. The cubes are made of many different kinds of stones with varyingdensities. Clearly their weight, not their size or other characteristics, was afactor in sculpting these cubes. In Egypt, scales can be traced to around1878 B.C.E., but their usage probably extends much earlier. Carved stones bearing marks denoting weightand the Egyptian hieroglyphic symbol for gold have been discovered, whichsuggests that Egyptian merchants had been using an established system of weightmeasurement to catalogue gold shipments and/or gold mine yields. Althoughno actual scales from this era have survived, many sets of weighing stones aswell as murals depicting the use of balance scales suggest widespread usage. Variationson the balance scale, including devices like the cheap and inaccurate bismarbegan to see common usage by c. 400 B.C.E. by many small merchants and theircustomers. A plethora of scale varieties each boasting advantages andimprovements over one another appear throughout recorded history, with suchgreat inventors as Leonardo Da Vinci lending a personal hand in their development. Evenwith all the advances in weighing scale design and development, all scales until the seventeenthcentury C.E. were VARIATIONS ON THE BALANCE SCALE. Although recordsdating to the 1600s refer to spring scales for measuring weight, the earliestdesign for such a device dates to 1770 and credits Richard Salter, an earlyscale-maker. Spring scales came into common usage in1840 when R. W. Winfield developed thecandlestick scale for use in measuring letters and packages. Asmentioned in response by Sri Narayanaswamy, weighing scales earlier weresubjected to corrosion. With the use of quality steel spring corrosion and elasticproblems are much reduced now. The quality of springs one can see inthe springs for holding cell/battery in wall clocks, cordless mouse, oxy-meter,BP meter etc. Bythe 1940s various electronic devices were being attached to these designs tomake readings more accurate. These were not true digital scales as the actualmeasuring of weight still relied on springs and balances. LOADCELLS, SMALL NODES THAT CONVERT PRESSURE TO A DIGITAL SIGNAL, have theirbeginnings as early as the late-nineteenth century, but it was not until the late-twentiethcentury that they became accurate enough for widespread usage. 17. Do spring balance or beam balancecame first in to use? Thebalance (beam balance and laboratory balance) was the first mass measuringinstrument invented. In its traditional form, it consists of a pivotedhorizontal lever of equal length arms, called the beam, with a weighing pan,also called scale suspended from each arm. The unknown mass is placed in onepan, and standard masses are added to the other pan until the beam is as closeto equilibrium as possible. Duringthe first year of my BSc one of the experiments were finding out the mass of asmall solid item using beam balance. The beam balance was placed on theexperiment table in an enclosure. In the centre of the beam the needle with markand either side at 1/10 cm distance marks. Weight had to be added in milligramsand arm set to Zero..... Weights were added n either side for this experiment.In 1970’s this type of balance was common with gold merchants. 18. Technically does the arm balancemeasures mass or weight? Althougha balance technically compares weights, not masses, the weight of an object isproportional to its mass, and the standard weights used with balances are usually labelled inmass units. Balancesare used for precision mass measurement, because unlike spring scales theiraccuracy is not affected by differences in the local gravity, which can vary byalmost 0.5% at different locations on Earth. Achange in the strength of the gravitational field caused by moving the balancewill not change the measured mass, because the moments of force on either sideof the balance beam are affected equally. IN FACT, A BALANCE WILL MEASURE THECORRECT MASS EVEN ON OTHER PLANETS OR MOONS, or any location that experiences a constant gravity oracceleration. Veryprecise measurements are achieved by ensuring that the balance's fulcrum isessentially friction-free (a knife edge is the traditional solution), byattaching a pointer to the beam which amplifies any deviation from a balanceposition; and finally by using the lever principle, which allows fractionalmasses to be applied by movement of a small mass along the measuring arm of thebeam, as described above. For greatest accuracy, there needs to be an allowancefor the buoyancy in air, whose effect depends on the densities of the massesinvolved. 19 Original balance Theoriginal form of a balance consisted of a beam with a fulcrum at its centre. Todetermine the mass of the object, a combination of reference masses was hung onone end of the beam while the object of unknown mass was hung on the other end. 20. off centre balance Toreduce the need for large reference masses, an off-centre beam can be used. Abalance with an off-centre beam can be almost as accurate as a scale with acentre beam, but the off-centre beam requires special reference masses forcalibration. InKerala we had such measuring equipment called KAZHANCHI KKOL which was a conical road withincreasing weight. Theitem to be measured was suspended at smaller end and strong movable holder ismoved towards the expanding conical side, where the road is horizontal, the pre-markedweight is read as the weight of the item. This was more used to weigh not veryheavy item. If I recollect smaller Kazhanchikkol was used to weigh gold silverand medicines. I will continue in next posting -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/thatha_patty/161457500.140934.1633589833072%40mail.yahoo.com.
