How do scales that are capable of measuring incredibly tiny amounts of things actually work?
In: Technology
At work we can measure dust measured in micrograms using a TEOM short for tapered element oscillating microbalance.
Dust is deposited onto a tiny filter at the end of a hollow glass tube. The tube is forced to vibrate using a small electromagnet. It has a natural frequency that it will vibrate at and the machine tries to keep it at that frequency.
As the dust level increases on the filter the frequency or tone of the tube changes much like a piano tuning fork, except this tuning fork is getting heavier.
The more mass on the end of the tuning fork the lower the frequency it will vibrate. From the change in frequency over time the weight of the dust can be calculated.
This is a somewhat simplified version what actually happens in the machine, one of the interesting things is that you can use this method in zero gravity or in microgravity such as onboard the ISS.
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