Sydex
Eagle Member
Your scale appears to be sitting on an irregular cloth surface. Could that compromise repeatability?
It makes the scale less precise. I worked as a lab tech for a plant biochem lab while in undergrad and part of my job included making sure the scales and other equipment was calibrated.
Basically, any scale that is not on a level surface that hasn't been on for a few minutes in a temperature stable environment will be off. It might not be by much, but it will be off. Some of the more sensitive equipment (talking scales costing as much as used cars) would register a false report just by having a hand on their table.
My procedure for calibrating went something like: 1) ensuring a level surface; 2) ensuring the scale was on for a few minutes; 3) calibrating; 4) ensuring there were no fans or other sources of air movement nearby; 5) calibrate again; 6) measure whatever needed to be measured.
Most of these cheaper scales usually have an margin of error of a gram to a milligram for a better one. Without proper calibration and set up, you'll likely be off by whatever the margin is or more. Most good scales will even let you know how heavy of a weigh boat to use. Without a perfectly flat and level surface, you'll likely get a little off too.
This is just a little bit of useless information I've acquired that has only ever now been useful when people want to weigh discs. But in the video posted, the most concerning thing is really that he's using an object bigger than the weighing platform to rest the discs on. Without placing the object to where the weight is focused in the center of the platform, you're going to be off a little.
Scales are fun!