Sneaky scales fudge weights deliberately.
I suspect that many modern, microprocessor -controlled bathroom scales have programmed in hysteresis to increase user confidence in the scale's accuracy. The scale remembers fresh measurements, say 166.2#, and if it next measures same weight +/- a little (within a short time), say 166.8#, then the scale decides to report the *original* measurement
166.2#. Neat. Sneaky. User believes the scale is highly repeatable.On such a scale, I weigh myself multiple times and get the same reading (to the 0.2#) each time. 166.2#, 166.2#, 166.2#, 166.2#, ... Then I weigh something different (myself holding a load), to reset the memory. Then I weigh myself again... Now, get something like 166.8#, 166.8#,
166.8#, 166.8#, ... very solid again, but 0.6# different from 1st series of measurements.I tried 6 models (2 or 3 brands) at a retail store display and find this "feature" common.
Is it important? Maybe yes in the following scenario -- in some sports like wrestling, boxing, judo, you have multiple competitors weighing in at the same time, same scale, with possibly very similar weight. Some competitors are concerned with as little as 0.25#. In this case it seems one competitor could inherit the weight measurement of the person in front of him.
In a perfect world, competition weigh-in equipment should be certified/calibrated. But since the bathroom scale appears so repeatable, some competitions now use modern, microprocessor
-controlled bathroom scales.
Somebody's going to say... "you shouldn't do that". Right, I agree. But (a) it's happening, because (b) this hysteresis (memory)phenomenon isn't widely known, I suspect.
Anyone care to confirm? Contradict? Repeat the experiment on their own scale? Comment? In my experiment I didn't bother to determine what weight difference resets the memory -- 1#? 1.5#?
Regards, John Ruckstuhl