Scales measure weight, which is a measurement of how much the force of gravity acts on a given amount of mass. Gravity varies slightly all over the Earth, so while a piece of coal may have the same mass, its weight will vary based on its location.
As the Earth is not a perfect sphere the strength of Earth’s gravity on its surface varies a bit from place to place.
So how does this affect my scale you ask?
In practical terms once a weigh scale has been calibrated in its location then gravity is no longer relevant. But what if the scale has been manufactured and calibrated in China, shipped to a Distributor in Tasmania and then sold to an end user in Townsville.
How accurate will the scale be?
The simple answer is they won’t. Even if the scale was recalibrated in Tasmania the scale would still need to be recalibrated in Townsville or adjusted using a gravity compensation feature on the scale.
A 100kg person would weigh 200g more in Tasmania than they would in Queensland. The gravity in Tasmania is 9.780ms while Queensland is 9.805ms. So your weight is largest in Tasmania and smaller in Queensland.
This scenario highlights
- The importance of having your scale calibrated correctly based on your location.
- Purchasing quality brand scales that have a gravity compensation feature or auto calibration feature.
- Purchasing from a supplier who understands scale calibration and has the expertise to assist you in your purchase.
How does gravity compensation work?
Most quality scales will have a procedure which is carried out on the scale to compensate for the gravity difference between the place of calibration and the place of use. It is a matter of changing the gravity acceleration value of the scale to the value of the area where it will be used. A sample of a gravity acceleration map is below.
Just for fun, have you ever wondered what you would weigh on the Moon? Gravity is about 1/6th the strength on the Moon as it is on Earth, so you would weight significantly less on the moon. The Exploratorium website has a fun page where you can calculate your weight on other worlds.
Happy weighing. Get your scales calibrated correctly and have peace of mind that your products and processes are being weighed correctly.
Best weighing scale which is calibrated:
A&D HC-i counting scale:
The A&D HC-i counting scale makes all your parts counting as breeze. With an easy to follow navigation system the HC-i scale makes for user friendly operation and gravity calibrated.