I thought I would try another online course and this one was on the Physics of COVID Transmission. Now I know a little bit about this to say the least and I even taught at the illustrious institution. After the first minute or so I was aghast. You see not at any time did the instructor define an aerosol. I know what they are, I spent a few years measuring them almost sixty years ago. But the instructor just went full ahead without any definition.
Now any High School student, at least in my day, God forbid not today and the current batch of useless material, but back when we learned Newtons laws of gravity, shoot out some particle and it is bound to drop, unless...
The unless was that it acted like a hot air balloon, namely the density of the object was less than that of air and so there was some lift. Then as the object cooled it dropped but at the same time collided with other particles and add on top electrostatic charges as well,
But this instructor just jumped from the undefined aerosol to a batch of nu-derived equations without any semblance of letting the student know what is happening. Feynman would be aghast. One must have a basic physical gestalt, not a pile of equations.
Then we assume, assume, assume to lead to the answer, whatever it may be worth. This is not science, it is graphic manipulation. But, and this is the deplorable part in my opinion, some "news" source will accepts it as proven science, publish it and we now have politicians adding another useless rule on top of a pile of others.
One should remember Feynman and the frozen cracked O ring on the shuttle. Put the ring in a glass of ice water, take it our and drop it, cracked. We all get the idea. I suspect the students would never be able to describe an aerosol.
Think hot air balloons!
After-all, if you plan to study aerosols you should at the very least define and describe them. We know more about angels on pin heads from this set of lectures.
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