What does the weighing scale we use in our homes actually measures? As weight should be in Newton and it measures in Kilograms so does it measures our mass ? Why we say that our weight is x Kilograms when we should say the weight is x Newtons , it is too confusing for me .
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Bathroom scales measure resistance. The springs can push back up to a certain amount of force, and the dial (or potentiometer in an electronic scale) is connected to the spring in such a way that how much it turns points to what fraction of the max force was applied.
Say a scale is rated for 300 pounds. A person who’s 150 pounds steps on, the spring compresses halfway and then hits the point where it’s pushing upward with the same force as the plate is being pushed down- that’s equilibrium. The dial is calibrated so that halfway is marked “150 lbs,” but what it’s really telling you is how far down the person pushed the plate before the spring started pushing back.
You can have fancier scales with magnetometers instead of a mechanical linkage, but it’s still following the same logic:
* The plate is this far away
* The spring stops up to this much force
* The spring stopped this much of the max force to stop the plate here
* Therefore, this is the weight that was applied to the scale
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