How come, when the front door of my house is open, a fly can enter my home easily, but not escape as easily out of the same door? (continued)
Anthony Woodward
Portland, Oregon, US
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There are many flies outside a house. The area of the walls of the house is much greater than the area of the doorway and most flies will hit the walls, but because there are so many flies outside there is a reasonable chance one will hit the doorway and enter the house.
Inside the house, the total area of the walls is much greater than the area of the door. The chance of one fly moving randomly hitting the doorway is small.
Ian Daniells
Kootingal, New South
Wales, Australia
With only one door open, your house is a fly trap. The insects are drawn in, perhaps by the smell of cooking. They try to escape towards light, but don’t grasp that glass is solid. You could open a door on the other side of your house. Oh, hang on; that won’t work if you are cooking; more flies will come in. In Australia, we have fly screens on windows and doors. That keeps insects out (and in!).
A Fly (aka Steve Tees)
Chelwood Gate, East Sussex, UK
Why do humans open doors to let me in and then immediately want me to leave?
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