Flies – I may be overthinking this

Denver doesn’t have bugs. That is one the things Mike & I both liked about it. There are insects, but they tend to crawl around and generally leave one alone. There are not many bothersome insects that “bug” one.

Rapid City has flies. Not at the “plague of locusts” level, but they’re around and they bug me while I’m sitting on the deck (which is currently just a flagged off section of the back yard, but I have a good imagination). So, I’m thinking to myself I’m thinking, “it would be easy enough to kill they flies in this 10×10 area, but would it do any good?”

If one models the situation statically with X flies per unit area (or unit volume if you want consider my deck 10x10x10), one just kills the flies in that area/volume and declares victory. I don’t think it works that way.

Is going to Boyle’s Law a step to far? PV=nRT contains all the relevant factors if one considers the flies to be molecules. The assumptions seem to hold:

  • Gases are made up of [flies] which are in constant random motion in straight lines. “straight lines” is vastly simplifying the flight path of a fly, but they might average out and molecules don’t travel in straight lines either (gravity, brownian motion, and electromagnetic repulsion/attraction, at least).
  • The [flies] behave as rigid spheres. That seems reasonable.
  • Pressure is due to collisions between the [flies] and the walls of the container. OK, this one needs some tweaking, but surely there is a fly version of the Pauli exclusion principle. They may not “collide” but they do resist occupying the same location. We’re also talking about a vast space (at least a city block), so its boundaries are not interesting.
  • All collisions, both between the [flies] themselves, and between the [flies] and the walls of the container, are perfectly elastic. (That means that there is no loss of kinetic energy during the collision.) This seems fair – the flies are generating their own energy, so any “lost” while avoiding each other and then “added” heading in a different direction can be considered an elastic “bounce”, don’t you think?
  • The temperature of the gas is proportional to the average kinetic energy of the [flies]. It’s going to be like measuring the temperature of space: The density is so low that even though the temperature is rather high, there’s still nothing there. (One does not freeze in space because of the temperature; it’s the pressure.)

The point of this dynamic analysis is that the interesting thing is not the few molecules that one plucks out, but rather how fast the surrounding molecules drift into the “low pressure” area created by the ones removed.

That means the interesting term is “pressure”. How does one measure fly-pressure?

See what I mean about over thinking?

It will be easier to demonstrate empirically: Buy a bug zapper and see if it keeps the deck fly-free.

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