Wednesday, 6 June 2018

Just How Important Is Calibration?

The question of calibration frequently arises with a new balance, and the answer is simple: most manufacturers recommend calibration before the first use. And if you use your balance at all, regular calibration is critical.

There are many reasons a balance needs to be calibrated. Variations in the environment can make a difference, and just the simple process of shipping can affect the mechanics of the balance.

Lab Manager is hosting an interesting article on balance calibration. Here is an extract:

“Balances react differently to changes in location. A less-sensitive balance, one that is readable to 1.0g for example, may not be able to measure a change in gravity when it is moved from one place to another. Highly sensitive lab balances will more readily display differences in gravitational forces. On the most sensitive analytical lab equipment, such as five-place, semi-micro balances, it is possible that a very small difference in location can cause large changes to the balance’s calibration.

For example, an analytical laboratory balance capable of weighing 100g, readable to 0.0001g, can detect very miniscule changes in gravity. If the balance is calibrated with a 100g mass and then moved upstairs three floors, the change in gravity will cause the balance to measure the 100g mass as 99.9970g, or 0.0030g less because it is farther away from the center of the Earth. If the balance moves north by 1,000 meters (1km), it will measure the same 100g mass as 100.0007g, an increase of 0.0007g, because it has moved closer to the North Pole. If it moves south by 1,000 meters, it would be measured 0.0007g less. If it moves east or west it would stay the same, as it is the same distance to the center of the Earth.”

For further details, see Lab Manager

Posted by Dr. Tim Sandle

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