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This reminds me of making a trip to a jeweler when I was < 10 years old, and noticing that they had a weighing scale that seemed to be down to decimal points of
by atonse 11mo ago
This reminds me of making a trip to a jeweler when I was < 10 years old, and noticing that they had a weighing scale that seemed to be down to decimal points of a gram (which I guess counts when you're weighing gold, etc).
And the numbers kept changing even when the scale was empty. I think I had a whole conversation with my grandpa about why that was happening, and we came up with "probably just variations in air/breeze around the scale causing them to change"
No idea if that's actually what it was, but it's plausible if you're doing sub-gram weighing?
- School-Cotton 11mo agoI have a scale in my kitchen that measures with 0.1g precision, and it doesn't do what you describe (change while you're not touching it). Perhaps technology has advanced since the anecdote you describe? Or maybe my scale is just lying to me.
- atonse 11mo agoHmmm then I bet it was a flaw. Or maybe modern scales have microcontrollers that adjust for this? This was a scale in a jeweler in India. It might have been in the late 80s or mid-90s. I might be misremembering too. So take my anecdote with a grain of salt.
- School-Cotton 11mo ago> Or maybe modern scales have microcontrollers that adjust for this? This seems likely to me.
- zahlman 11mo ago> So take my anecdote with a grain of salt. Oh, come on. Surely the scale wasn't that precise.
- ceejayoz 11mo agoYour scale may smooth out the fluctuations automatically. Mine takes a little while to notice when I'm adding something like a tenth of a gram of yeast to a recipe.
- School-Cotton 11mo agoYeah, I'd guess this is what's happening.
- Scene_Cast2 11mo agoMost likely the op amp (or whatever gain stage) noise. After a certain point, you get thermal noise. But with such scales, low sample rates and averaging are key.
- embedding-shape 11mo ago> No idea if that's actually what it was, but it's plausible if you're doing sub-gram weighing? Yes, even dust particles landing on the scale can impact the reading, which is why when you're measuring really small things and want to be precise, you usually have a little glass/plastic cube around the entire thing too. Also frequently used for people who measure drugs for various purposes.
- jamessb 11mo ago> why when you're measuring really small things and want to be precise, you usually have a little glass/plastic cube around the entire thing too. These weighing instruments with draft shields are usually called analytical balances: https://en.wikipedia.org/wiki/Analytical_balance https://en.wikipedia.org/wiki/Analytical_balance