Weighing scales have been around since time immemorial and that's the plain reality of it. The truth is, even with all the investigative techniques we have, it has been hard for the archaeologists and scientists who've tried to attach a date to this device. The weighing machine is such an essential to any venture that any usage will probably predate any evidence that's been found. Disregarding this argument and just sticking to the facts, the earliest evidence of a weighing scale dates back to 2400 – 1800 B.C. Over time, society in its continual useof this device has made improvements and refinements of its functions and so has resulted in the emergence of several breeds of weighing machines and from the low tech to the high tech, each one deserves to be looked into to show how each modification has made the humble weighing machine not so humble at all.
The Balance, with its many names such as balance scale, beam balance and laboratory balance is one of the first to be invented and used by the masses. Its most basic function is mainly dependent on two pivoted arms of equal lengths with pans suspended on each arm. The variable mass being weighed is placed in one pan while standardized weights are placed on the other pan. The weight of the unknown mass is decided upon when equilibrium between the two arms is achieved. This equilibrium is mainly achieved when the two masses on thepans exert the same amount of torque. Further, more advanced models of a balance may have a slider weight that can be slid across a graduated scale. This provides greater precisionin measurement. One thing interesting about the balance is that it measures mass instead of weight and since mass is proportional to weight, knowing one will give away the other. Thebalance is also one of the most accurate you can ever use. Weight is affected by gravity and since the value of gravity may well be different by as much as 0.5% at different locations on the globe, you might get some disparity with your results. However, since gravity exerts equal force on both the unknown mass and the standard set of weights, you'll get a moreprecise reading. Leonardo Da Vinci is said to have played a huge role in the early improvements made on this type of weighing machine and so it is not with great surprise since it was the most popular during his time.
Spring scales come in two types. The first kind of spring scale is where the spring stretches, this type is commonly found in a produce market while the other types is where the spring compresses like in your everyday bathroom scale. Both of these kinds of weighing machines work through the force of gravity acting on an object and through knowing the proportional constant of the spring being used in the weighing device. As mentioned earlier in the section discussion balances, gravity has a discrepancy of 0.5% depending where you're located on the planet and this renders readings from a spring scale, not erroneous, but not precise. Temperature also plays a role in the function of spring scales since this affects the proportional constant of springs. One thing that they do to compensate for this is to calibrate the scales to the force of gravity in the locality where the scale is to be used and further uses temperature compensated springs so as to get more accurate results from measurements. The electronics version of the spring scale is the strain gauge scale. This scale works bymeasuring the degree deflection of caused by the unknown weight. This scale has become more common in the past decade since it is only limited by the resistance of the beam to deflection. This
type of scale has a range of models that have the sensitivity to measure objects of a few grams to those that have the capacity for that of a few tons.
Hydraulic or Pneumatic scale
The hydraulic or pneumatic scale is another type of scale that has seen greater popularity in the past decade. As we make structures bigger and bigger, we've had to measure weight for heavier and bigger objects and so the calling of the hydraulic scale. This type of measuring machine is found in high-capacity applications such as that of a crane scale. To put it simply, a pneumatic scale is simply a closed cylinder with oil in it and with a piston fitted inside the cylinder. The reading or measurement is based on the amount of gravitational force applied on the oil through the piston. This reading is shown through a dial that shows the force that is compressing the oil. Since there are no springs or adjustable weights, this is a veryconvenient and simple device to use.
The technological advancements of measuring machines have come to its pinnacle but yet, further developments are still being made to all the various systems described here. At its present state, we're capable of measurements from the most minute objects such as those found clinging on a grain of sand, to those measuring over a thousand elephants, plus, the spectacular accuracy and precision of measurement we have not is truly astounding as well. The humble weighing machine has truly earned its place in mans' select choice of tools and so continues to constantly prove its weight in gold.
To all of you, from all of us at Scalesmart & MWS Ltd