Why do bags of water hung from ceilings kill flies?
538028
It doesn't kill them, just repels them.
918749
That's basically fly crap. they lay their eggs on organic material so the maggots can eat off, so unless there's raw meat on your wall you shouldn't have a problem.
626205
ok, it would freeze quickly (not explode-it is made of solids and liquids, which don't expand in vacuum). But for fun, assume it doesn't freeze or die of hypoxia.  Since there isn't any air, there is nothing for the wings to beat against, so it would flap it's wings and just stay in the same place- The motion of the wings might cause it to start rotating, though-so I would imagine the fly (which is a magic fly that doesn't dry up, freeze, or need oxygen) would just spin around in a tiny circle right where it is.
898517
OK if you mean water only I assume that you require to dry out compressed air lines.  This is done by passing the air through an air drier as the air is cooled the water is separated and discharged to atmosphere or drain.  This is one method I am not sure about others.
75589
I don't know-- but it reminds me of an old joke.\n\nA scientist studies a fly. He claps his hands near the fly, and it flies off. He then captures the fly and pulls its wings off. He then claps his hands again, and the fly just stays where it is. The scientist concludes that if you remove the wings from a fly, it goes deaf.
1023731
Bacteria in the water has killed them off.
1184123
Some are full of maggots that they are going to land and lay soon. Some may be of a different fly species that are naturally larger. I believe that 'housefly' covers a several different kinds. And there is probably a bell-shaped curve that covers their sizes, like a lot of other things.
513551
A house fly in space would float weightless without moving.  However, if it started to flap its wings, it would create thrust and move by pushing the oxygen in the cabin.  Though, if it were outside the cabin (and able to breathe), it would flap its wings with no result as outside space is a vacuum and the flapping would creat no thrust.
752099
They are not harmful, they do not bite. They jump really crazy and are annoying, since they will try to get into the rest of the house. You can try vacuuming them up, or try drying out the basement, since they like a damp environment. Try to find where they congregate and suck them up, seal the bag and dispose of it. Find cracks where they are getting in from outside and seal them. Good luck!!
690234
IT DEPENDS OH HOW HIGH THE CEILING IS IT LOOKS TO ME THAT THE FLY HOVERS IN A SORT OF SWINGING  FORM THEN FLIPS BEING THAT ITS LEGS ARE ALL STICKY FROM ALL THE REGURGITATING
1017672
Because insects use a different type of respiratory system than people do.  Rather than breathe air in through centralized nostrils to their lungs, they breathe air in through a de-centralized network of smaller tubes located all over the surface of their body known as spiracles.\n\nBecause of the large area they take oxygen in through, they are able to store enough air to breath for an extended period of time when deprived of oxygen, as they are when they're trapped underwater.  The water's surface tension keeps it from draining into the spiracles on their body, which is why it simply doesn't flood their respiratory system and drown them.  \n\nUsing this method of respiration allows roaches extra time to find their way back to a surface where they can get more air, and cockroaches aren't too particular about where they live, being well armored and equipped to survive in just about any conditions.\n\nSo, when you flush the roach, it just holds its breath, goes along for the ride, and when it gets to the sewer either drowns eventually or just crawls its way to the surface and moves on with life.\n\n\nP.S.-- This is also why pesticide makers have to either find an ingredient to break down the surface tension of water they suspend their poisons in or just go with another liquid base for their poisons... if the surface tension of the water is normal, the poison just sits on the outside of the roach's dead armor shell, and it holds its breath and waits until it dries off and the poison is no longer an issue.\n\nP.P.S.-- Have you seen how misclassified most of the questions on Yahoo Answers are?  Folks are asking jokes in philosophy, biology questions in engineering, sexual health questions in cooking, cooking questions in religion, and questions about dogs in the math section.  I'd be willing to bet a lot of people don't bother to pay very much attention to where the question is classified any more.
1177301
LOL\n\nIts actually some flies buzzing around you.  Take a shower.
349260
They are a disgusting type of fly.  You usually see them joined end to end during "love bug" season and they are everywhere!  Your windshield gets plastered with them.  We were in Florida one time during the height of love bug season (September)...never again!  I am not aware of any purpose they have unless it is irritating people.\n\nFor more info and to see what they look like:\nhttp://insects.tamu.edu/extension/bulletins/uc/uc-009.html\nhttp://www.floridaenvironment.com/programs/fe00508.htm
340723
So that insects don't fly into our mouth.
242174
The housefly (also house-fly or house fly) (Musca domestica) is the most common fly occurring in homes and indeed one of the most widely distributed animals and the most familiar of all flies; it is a pest that can facilitate serious diseases.
307036
The clouds hang in the air due to buoyancy (density of water vapour is less than air). At higher altitudes the air becomes thinner and force of buoyancy is lesser. so they cant hang at higher altitudes.
434885
the only thing that I can think of, is that when you are putting so much water into the fly it messes up it's electrolytes...therefore the nerves can't do anything because they will never reach their threshold and have an action potential.  Mostly the potassium and the sodium, and so when you put salt (which contains sodium) on the fly is causes the electrolytes to re-balance.\nMaybe the fly isn't really dead...maybe it's just paralyzed?\n\nThis is just a theory since I've never heard of this phenomenon myself.