From the one that we stand on in our bathrooms to see how well (or badly) we are doing on our diets to the ones that determine what our meat, produce, or diamonds are going to cost us, scales play an important part in the day to day life of most people – and oftentimes in ways we don’t even realize.
Scales have been used for thousands of years – dating back to ancient Egypt and most probably even earlier – to determine the weight of things in relation to other things, and therefore their relative worth. In some applications, scales perform exactly the same function today.
In days gone by, scales played a critical role in the advancement of early civilizations, as they allowed a way for people to establish a point of reference for systems of barter. As early civilizations did not have a universal form of currency, the weight of one commodity vs. another was often the accepted method of determining what a fair rate of exchange would be. For example, a certain weight of bronze might be considered an acceptable trade for another weight of animal skins.
Although early scales were often imprecise – and could be easily manipulated to the advantage or disadvantage of one or the other party involved in any transaction – they were nevertheless one of the earliest machines invented by human beings to establish a mathematically-based system of constants and standards, and thereby provide the most basic benchmark for trade between different cultures.
Today’s scales are far more sophisticated, but serve basically the same function; they determine weight in preset values (pounds, kilograms, carats, etc.). Scales manufactured today fall into three very broad categories: mechanical, digital and balance.
Mechanical scales normally use springs with a preset tension and in effect measures the force (or resistance) of an object that is placed on them; the more force, the heavier the object. These scales normally use a mechanical gauge to display the weight.
Digital scales work in much the same way as mechanical scales. In smaller digital scales a strain gauge is used to measure an object’s weight and transmit the information to a microchip which displays the weight in numbers on an LCD (liquid crystal display) panel. In larger industrial scales a load cell – which is a type of hydraulic transducer – is used in place of the strain gauge. Digital scales utilize batteries, are connected to an electrical outlet, or hardwired to another power source. Some digital scales can be programmed to remove tare weight (the weight of containers or packaging for commodities).
Balance scales (often called pendulum or counter-weight scales) are the earliest type of scale and date back thousands of years. Balance scales often utilize a straight, rigid, balanced beam; containers or panels of equal weight are placed on each end, and the objects to be weighed (or counter-weights of predetermined values) are placed on either end. When the beam is level, the weight is equal. Most modern versions feature a weight (or beam) bar to which sliding counter-weights are attached and slid along the bar to balance it. The least popular type of scale still in use, balance scales can be some of the most accurate and are still widely used in some applications (for example, by physicians) today.
Both mechanical and digital scales are often interchangeable – although more sophisticated specialty scales are usually digital. Some scales feature both digital and mechanical displays.
So what are some of the most commonly used types of scales?
1. Bathroom Scale
One of the most widely used of all scales, the bathroom scale is used to measure a person’s weight. Available with digital or mechanical displays (some recent hybrids offer both) bathroom scales are usually flat, compact and sit on the floor; a person weighing themselves (or someone else) stands on the scale, which will then display their weight. Most bathroom scales manufactured today feature a non-slip standing surface or covering.
The modern bathroom scale evolved from what was called the penny scale: a massive machine often weighing 200 pounds or more, normally found at the apothecary, or on street corners. People would put in a penny and then stand on it to see how much they weighed. The smaller version found in most households today did not appear until the late 1940s.
Bathroom scales will typically measure up to 400 pounds (180 kg), although some are calibrated to weigh up to 600 pounds and above. In the last decade or so, specialty digital bathroom scales that measure BMI (body mass index), body fat, bone, and muscle mass, as well as weight, have been developed. Many of these scales can be connected by Wi-Fi to other ‘smart’ devices.
Mechanical bathroom scales can be had for as little as $10, while some of the more sophisticated multi-purpose digital models can run over $300. An extremely popular item in the US and Europe, it is estimated that over two billion dollars are spent each year worldwide on bathroom scales, with almost half of that being spent in the United States alone.
2. Kitchen (Food) Scale
Although it has not yet achieved the must-have status of the bathroom scale, as more and more people have become conscious of their eating habits in pursuit of a healthier lifestyle in the last couple of decades, the kitchen scale has grown in popularity. Kitchen scales are usually quite compact, are placed on the counter when used, and are easy to wash and store.
Available as mechanical or digital machines, kitchen scales come in two basic designs; a flat version on which food is placed on a metal, plastic or rubber surface to be weighed, and a version that utilizes a glass or plastic bowl (usually detachable and machine washable) into which the item(s) to be weighed are placed.
While measuring the ingredients needed for a recipe has traditionally been done by volume (a cup of sugar, etc.), measuring by weight allows cooks to follow those recipes with far more accuracy. For example, a cup of cheese will have a different weight depending on whether it is cubed, shredded, or grated. Virtually all diet cookbooks include both volume and weight measurements in their recipes, and newer regular cookbooks have started to follow suit.
Kitchen scales with bowls tend to be the more popular of the two types mentioned above, and with good reason. Firstly, they allow liquids and loose items (flour, sugar, etc.) to be measured without the need to weigh a separate container of your own. Secondly, they allow the user to weigh multiple items at the same time in one built-on container, which helps save time and effort.
Most kitchen scales will accurately weigh twelve to fifteen pounds of material, with some going up to twenty pounds and more. Kitchen scales normally cost between $8 and $50 with accuracy, style, design, and extras (conversions between units of measurement, AC adapter, etc.) influencing the price.
These scales are also often used by craftspeople and artisans.
3. Physician Scale
Once your waiting room time is over and you enter the examination room, the first thing the doctor will usually have you do is step on a complicated-looking and normally quite a tall scale to see what you weigh.
The physician (also commonly called doctor’s) scale is a far more accurate scale than the one you step on in your bathroom, and normally only measures your weight – although some come with a built-in height measuring rod. These scales are usually only found in doctor’s offices, hospitals or clinics.
While some doctors and hospitals have switched to using digital scales, the majority of physician scales manufactured today are highly accurate balance scales which utilize a slide bar on the top. After the patient steps on the scale, the doctor or nurse will slide small counter-weights across the bar, upon which increments of weight are printed, until the bar balances. Most bars will have two slides – one which measures pounds (or kilograms) and another that measures ounces (or grams) to provide a very accurate weight.
Most physician scales weigh between 35 and 50 pounds, although some older versions can weigh 100 pounds or more, and will normally measure weight up to 400 or 500 pounds. Many are available with conversion kits that will allow them to measure up to 700 pounds. Specialists in the treatment of morbid obesity will often utilize a bariatric medical scale, which will measure up to 1,000 pounds. Those equipped with height measuring rods will usually measure up to seven feet.
Physician scales will usually cost between $150 and $300, while some heavy-use models (particularly those used in hospitals) can run $500 and higher.
4. Grocery Scale
Grocery scales come in many shapes and sizes, and are used to weigh meat and poultry; seafood; deli meats and cheeses; fruits and vegetables; nuts and some candies – the list goes on and on. One of the most widely utilized of all industrial scales, the grocery scale has been used for hundreds of years to determine the price of the food we eat.
Grocery scales are used in food stores and supermarkets, farmers markets, bakeries and candy stores, seafood markets and by butchers – effectively anywhere a non-prepackaged food commodity is sold by weight.
Grocery scales have evolved over the centuries. In the past, foods were weighed using balance scales, sometimes weighing the food against other commodities (for example, a certain weight of vegetables would buy another certain weight of meat), or using preset counter-weights to determine the price in money. The advent of the mechanical grocery scale allowed merchants to sell groceries for a predetermined price per pound or kilogram (for example, ham might be $0.50 a pound, apples $0.18 a pound, etc.) which helped to standardize food prices.
While mechanical grocery scales are still used in some small ‘mom and pop’ type grocery stores and at farmer’s markets and road-side fruit and vegetable stands (often utilizing a basket below the scale; weight is determined by the commodity pulling down on the gauge), the majority in use today are digital – and often quite sophisticated – machines.
Most grocery scales today display the weight, price per pound, and the total price of the order. Many have front and back display panels, allowing both the customer and merchant to see the information. Some have built-in label printers which will print the weight, price, UPC barcode, and RFID tag, allowing for quicker checkout and returns.
In the United States and many other countries, grocery scales are government regulated (often by a state’s department of agriculture) to ensure their accuracy. Most grocery scales are tested every one or two years.
Grocery scale prices vary wildly, depending on the type and additional features. The most basic type of digital grocery scale can usually be had for around $100 while heavy-use, more sophisticated machines with all the added bells and whistles can cost $1,500 or more. Most digital grocery scales will determine weights up to between 10 and 60 pounds.
5. Veterinary Scales
Veterinary (also called pet, animal, and livestock) scales are used in veterinary clinics, wholesale meat producers and on some cattle, pig and horse ranches to determine the weight of animals. As is the case with human beings, an animal’s weight can give an indication as to its general health; unlike human beings, they can also often determine some animals’ value. Veterinary scales come in many different sizes, based on the size and weight of the animals to be weighed.
Those found in veterinary clinics that normally service household pets exclusively are usually digital machines that serve the same function as bathroom scales, only with a larger platform upon which the animal being weighed stands (or is placed). In some cases, the LCD display will be a part of the scale, while in others it is connected by a cord and mounted on a wall.
Most scales used in veterinary clinics feature a non-slip, washable rubber platform, in case Fido has an accident while being weighed. Because they are quite weighty themselves, they will also often feature handles and rollers for easy movement. Most clinics utilize scales that will determine weight up to between 300 and 600 pounds and will cost anywhere from $200 to $500.
Larger animals like horses and cows, of course, require larger scales. Large animal scales that can determine weights up to 4,000 pounds are widely used by rural vets, farms and ranches, and in industrial applications such as slaughterhouses. Roughly the same design as those commonly used in clinics, large animal scales are usually digital, and are often battery operated for use ‘out on the range’. The LCD readout is usually mounted on a wall (or a pole for portable scales) separate from the scale itself. These scales will normally run between $800 and $2,000.
6. Baby Scale
Once almost exclusively found in GP, OGBYN, and pediatric medical offices and hospitals, baby scales have grown in popularity in the last couple of decades as a household scale. A baby scale, as the name indicates, is a scale used to measure the weight of infants. They are also often used to measure the weight of small pets, such as cats or guinea pigs.
Most baby scales today are digital, and feature a curved, detachable and washable plastic tray on the top into which the infant to be weighed is placed. The tray is attached to the scale either directly, or using footings which evenly distributes the weight on the scale; these footing often have locks to improve stability. Many newer baby scales will convert into toddler scales by simply removing the footings.
Home baby scales will usually measure weight up to 40 or 60 pounds in increments of one half-ounce, while those used in medical offices will be more accurate. Professional medical baby scales can cost hundreds of dollars, while a good quality, convertible home version will usually cost between $30 and $60.
7. Jewelry Scale
Jewelry scales are a type of specialty scale used in the wholesale and retail jewelry trade. Jewelry scales are used to measure the weight of precious metals (gold, silver, platinum) and stones (diamonds, sapphires) and can be designed to measure by the ounce, gram, carat, pennyweight, and troy ounce. Most of today’s digital jewelry scales will automatically convert the readout to any of these units of measurement and some others.
Because of the very high value of the materials, they are designed to weigh, jewelry scales are among the most accurate scales manufactured today. They are usually calibrated to report weight in increments of 0.1g (used for larger silver and bronze objects); 0.01g (used for gold and silver jewelry and bars); and 0.001g (used for diamonds and other precious stones).
While in the past pendulum-type balance scales with a very wide range of counterweights often going down to 0.01g were used to measure precious items, today’s jewelry scales are almost exclusively digital. In the US, most jewelry scales used by reputable jewelers and wholesalers are certified as ‘Legal for Trade’ by the Department of Weights and Measures and are inspected on a regular basis to ensure their accuracy.
Certified, professional jewelry scales come in a wide range of prices which are determined by the calibration and accuracy of the machine. Less accurate scales will usually run between $1,200 and $1,500, while those measuring down to 0.001g will often run $6,000 and higher.
Far less accurate ‘personal’ jewelry scales are also becoming popular, and can usually be found for under $50.
8. Shipping Scale
Shipping (also sometimes referred to as postal or receiving) scales are widely used by shipping and trucking companies (USPS, UPS, FedEx, etc.), airlines and railroads, as well as business and industry, to determine what it will cost to move an object from one place to another based on its weight.
The cost to ship items is usually determined by either a flat weight rate (for example, a first-class postage stamp in the US reflects the cost of shipping a letter weighing one ounce or less anywhere in the country), or a calculation of weight and distance and sometimes the type of service (for example, same day or overnight), depending on the shipping company.
Generally speaking, most shipping scales will measure down to .5 or .25 oz, and up to anywhere between 50 and 500 lbs. Some industries that produce heavy products will utilize shipping scales up to 5,000 lbs.
Most shipping scales today are digital, and will often have a feature that will make the weight/distance calculation. Some can be programmed to display both commodity and tare weights. They will usually be either desk/counter mounted, or bench/floor mounted, depending on what they will typically be weighing.
Good quality smaller shipping scales primarily used for letters and small packages will usually cost between $30 and $90, while those used in heavier industries and high weight shipping services can run $6,000 and higher.
9. Laboratory Scale
Laboratory (also called scientific, research, pharmacy, and HCPB – High Capacity Precision Balance) scales are the most accurate of any scale manufactured today. Laboratory scales are widely used in medical, university, and pharmaceutical research facilities; hospitals and pharmacies; some manufacturing industries; and the nuclear power and medicine industries. These scales are almost entirely digital.
Laboratory scales are used when pinpoint accuracy of weight measurement is needed – particularly in the cases of hospitals, pharmacies, and pharmaceutical manufacturers, where it can often be a matter of life and death. Most of these scales will be calibrated at least down to the milligram (1/1,000th of a gram), the standard unit of measurement for most prescription medicines, while the most sophisticated type of this scale (called a microbalance) can measure to one nanogram – one billionth of a gram.
The most common type of laboratory scale (and the only one any of us are ever likely to see) is the pharmacy scale. These will usually be calibrated down to .25mg and are used to measure the weight of pre-prepared pills and liquid medicines, as well as compound medicines made by the pharmacist. Like grocery scales, many come with a built-in labeling feature. Some will also come with pill counters to help ensure the pharmacist’s accuracy, and a feature for eliminating tare weight.
In terms of cost, the scales commonly used by pharmacists tend to run between $1,000 and $2,500, depending on features and durability. Research and HCPB scales will usually start at $20,000 and can run into hundreds of thousands of dollars for highly specialized types. Scientific scales are not normally offered as a consumer commodity.
10. Truck Scales
Moving from measuring the lowest weights to some of the highest, truck (also called railroad or weighbridge) scales are the largest scales commonly used today. Mostly utilized by the trucking, overseas shipping, and railroad industries, as well as law enforcement, truck scales are used to weigh entire trucks, overseas shipping containers, and railroad cars – either empty or fully loaded.
Normally installed on a concrete or steel foundation, truck scales can be over eighty feet long. Both mechanical and digital truck scales are in common use today; because of the weights they deal with, digital truck scales utilize a load cell to determine weights. Many newer truck scales are connected to computers which the operator can use to eliminate tare weigh (so that only commodity weight is registered) as well as print labels and specification sheets.
In their law enforcement application, truck scales are installed in weigh stations (normally operated by state police and country sheriffs’ offices, and some bridge authorities) on highways and near bridges and overpasses which have weight limits. Tickets for being over-weight – particularly on bridges – can cost a driver tens of thousands of dollars. They are also used to determine the toll charged for trucks to cross some bridges.
Truck scales will usually be calibrated up to 200,000 pounds, and sometimes more. The cost for truck scales can run $10,000 to $50,000 and higher, not counting installation. Most of these scales are regularly inspected by state agencies.
11. Hanging Scale
Also referred to as a butcher, luggage or sportsman’s scale, the hanging scale is a basic, lightweight scale that is hung on something (pole, door, tree branch, etc) by a built-in hook. A second hook hangs down from the scale, and whatever is to be weighed is attached to it; weight is determined by the object pulling down on the scale.
Hanging scales are widely utilized by butchers and the meatpacking industry to measure the weight of large quantities of uncut meat (for example, a side of beef). They are also often used by hunters and fisherman to weigh larger animals and fish, often at the point of kill or catch. Some smaller versions are used by consumers to weigh their luggage and are marketed as luggage scales.
While some (particularly luggage) hanging scales are digital, due to them often being used in refrigerators and freezers by butchers and outdoors by sportsmen, most hanging scales are basic, lightweight mechanical devices, and are often weatherproofed. They will usually measure weight in a range of up to 350 to 800 pounds.
12. Counting Scale
A relative newcomer to the industry, the counting scale is a device that calculates and measures the number of an item of a known weight. For example, a ball-bearing manufacturer’s product might weigh a standard one pound each; when the counting scale reaches 100 lbs, you have 100 ball-bearings.
Counting scales are almost exclusively used in the manufacturing industry where the commodity produced is always of known weight, and is sometimes used in high-speed product packaging determined by weight as opposed to volume. They often feature a tare function to remove the weight of the packaging for measuring the number of items in already packed containers.
13. Dimensional (DIM) Scale
There is an old trick question that goes: Which weighs more – a pound of feathers or a pound of bricks? The answer, of course, is usually that they both weigh the same – unless you are in the shipping business considering how much room each will take up on your truck. The fact is that the volume of a pound (or a ton) of feathers is far greater than bricks, hence the container used to ship them (and therefore the dimensional weight) will be dramatically different.
Dimensional scales calculate dimensional (or DIM) weight by multiplying the height, length, and width of a container and ignoring the weight of the contents. These scales are used mostly by shipping companies and the manufacturers of low weight, high volume products (such as shipping noodles, some foam rubbers, etc.) for which standard weight-based shipping charges do not make economic sense. A specialty scale not in common use, dimensional scales are almost always digital machines.
Lisa has a Bachelor’s of Science in Communication Arts. She is an experienced blogger who enjoys researching interesting facts, ideas, products, and other compelling concepts. In addition to writing, she likes photography and Photoshop.