Maybe you’ve visited a restaurant and seen clear, water-filled bags hanging on the doors or gripped up in the outdoor dining area.
You might ask yourself, “What the heck is this all about? Some crazy voodoo magic?”
While it really looks like a voodoo thing, these hanging bags are all about driving pests away. People hang these bags outside their homes, businesses and even in their barns to drive flies away.
Not only are flies incredibly gross (like hanging on a poop), they’re also incredibly annoying.
Insects and ticks are able to transmit a number of diseases caused by infectious agents: viruses, bacteria, and parasites.
Why it’s actually true, reported by HowStuffWorks:
The water bag method of fly repellant has many supporters, from restaurant owners to backyard grill-masters. Many success stories ranging from the mild to the miraculous litter the Internet.
So how does the method drive flies away? Some insist the flies perceive the clear liquid as the surface of a body of water. Others claim the insect flies away at the sight of its own magnified reflection. But the most popular reasoning that pops up among entomologists and patent-filing entrepreneurs is simple light refraction.
Refraction takes place when a clear or opaque object, such as a piece of glass or a bag of water, alters the course and velocity of light. The rays of light, which normally travel in a straight line, bend. This effect is responsible for a number of optical illusions, such as mirages, that occasionally baffle humans as well. For more information on refraction, read How Light Works.
The insect’s head mostly consists of a pair of large complex eyes, each of which is composed of 3,000 to 6,000 simple eyes. These eyes can’t move or focus on objects like human eyes, but they provide the fly with a mosaic view of the world around them. Each simple eye provides one small piece of the puzzle, much like the way a screen’s pixel delivers one detail of the larger picture.
A housefly bases its sense of direction on the direction sunlight comes from. Some entomologists believe that when these complex, sensitive eyes experience refracted light, the insect becomes confused and flies away.
While some supporters claim water bags keep all kinds of flying insects away, most report success with complex-eyed insects, like houseflies.
What can we do?
What grinds my gears is how when I open my door for just five seconds, flies will make to get in the house! It’s as if they were waiting for that perfect moment to sneak in. And on the contrary, when they want to leave the house, they just can’t find a wide open window!
If you like having exploded insect particles all over the place, you can get a bug zapper.
But if you want a less violent and passive approach, perhaps you should give the following anti-fly contraption a try.