The point is subtle but important and can be best explained by imagining how such a contraption would work on the moon. It would function just the same. This is because, while the weight of an object on the moon is one sixth what it is on Earth, the mass remains the same on either end of the balance. Technological advances have allowed engineers to come up with improved balance that no longer require pans with known weights. An analytical balance now contains a load cell that is displaced when weight is placed on top of the pan.
The amount of displacement is measured and a current is sent to the electronics of the balance, registering the displacement and measuring the mass of the object being weighed.
A scale, however, doesn't measure mass but weight. If you were to take a scale with you to the moon, it would tell you that you weigh one sixth what you did on Earth. That's because there are force gauges inside the scale that operate using Hook's Law. Ensure that nothing comes in contact with the analytical balance.
If anything touches or rubs against the balance, it will cause discrepancies in the readings. Some balances use magnets as a part of the weighing system. Therefore, placing the balance near magnetic equipment or weighing magnetic sample can result in erroneous readings. The scale or balance must be placed on a level surface. Precision balance scales weigh the materials assuming that the load is applied parallel to the force of gravity and perpendicular to the weighing platform.
Make sure that the AC source is properly grounded to prevent the build-up of static energy. Secondly, ensure that the chassis is grounded to avoid electrostatic discharge. Unlike metal containers, plastic and glass weigh containers can hold an electric current. Static charges can result in non-repeatable measurements or drifting measurement readings.
Even an accurate weight scale can provide incorrect readings in such cases. Lab workers need to handle the samples with care. These standard weights have precise, specific mass, and allow a way to check the accuracy of the balance. The term calibration refers to the process of adjusting the output of a scale or balance against a object of known weight. Many different types of substances can be weighed in the lab. One application of an analytical balance is measuring liquids.
This is critical for centrifugation experiments. One key aspect is making sure ultracentrifuge tubes have the identical mass or else the rotor will not be balanced, and cause big problems!
In addition to weighing liquids, animals and even insects such as drosophila and mosquitoes are weighed using balances. In this video, we showed you the different types of balances, how they work, how to use a balance, important tips for weighing substances, and some additional uses for balances in the scientific laboratory.
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Weigh boats are used when a large amount needs to be weighed out. Analytical balances are so sensitive that even fingerprints can cause readings to be inaccurate. Bear in mind that all of these types of balances may be referred to as scales in some literature, even that coming from manufacturers. For example, Torbal has a Laboratory Balances category , but refers to all of its balances as scales. In addition, Mettler-Toledo, a worldwide industry leader in weighing solutions, has product literature for one of its analytical balances that refers to the product as a balance, a scale, and a balance scale.
As mentioned, scales are often used to weigh larger masses, such as raw materials, reagents, and products in a production setting. However, they may be used in commercial or household settings to weigh smaller masses, such as produce in a grocery store, or ingredients for baking. There are two main categories of scales: mechanical and digital.
Within these categories, there are a plethora of different types of scales, including bench scales, home weighing scales, kitchen scales, and so on. Below are just a few of the scales you might see in use:. A home weighing scale, an Ohaus Checkweigher , and a kitchen scale. To add to the confusion, compact or portable balances are very often referred to as scales.
However, this also leads to practical differences such as the mechanisms via which the different models work, the accuracy of their measurements, and the types of applications they can be used for.
Aimee breaks down complex science and technology topics to help readers digest concepts and troubleshoot issues. She has well over a decade of experience in a laboratory setting, completing a degree in Medicinal Chemistry and working as a chemist for a multinational cosmetics company before pursuing her passion for writing.
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