Ziploc Bags Full of Pennies and Water Keep Flies Away- Fiction!
Summary of eRumor:
Ziploc bags filled with water and pennies can be used to keep flies away.
Ziploc bags full of water and pennies don’t act as a homemade fly repellent.
This rumor has been circling the web for years, and people have been using it to scare away flies for even longer.
The idea is that flies have poor eyesight, and water-filled bags create some type of optical illusion that scares them away. The most common version claims that light refracted in the water confuses the flies. Another version claims that flies are scared by their own oversized reflections in the bags.
First, the claim that flies have poor eyesight is false. Their eyes are made up of thousands of individual lenses that can see polarized light and color spectrums that human eyes can’t:
“House fly eyes can recognize even the slightest movements in a wide field. This allows the fly to see a far wider range, as well as detect and react to movement at a quicker pace than species with simple eyes. This is the reason that it is extremely difficult to swat a house fly.”
That doesn’t mean all of those lenses don’t haywire when a fly looks into a bag of water, but experts say that it’s unlikely. A bug expert with the Audubon Institute told the New Orleans Times–Picayune he had experimented with the water bag trick, and it didn’t work:
“(The bug expert) points out that flies are seasonal, they’re affected by wind, rain and other factors. There are lots of reasons people might come to believe the folksy water bags scare them off, but in his scholarly view, those reasons don’t, well, hold water.”
The TV show “MythBusters” also experimented with the homemade flytrap and reported it to be a bust:
“The Build Team made a rig consisting of three chambers separated by trap doors. The first chamber would hold the flies, the second would hold some rotten meat, and the third would hold both rotten meat and a bag of water. They then released over 5,000 flies from the first chamber and waited to see how many flies would go into each of the other two. After the chambers were sealed off, they let all the flies die and collected the corpses to weigh for comparison. The chambers with and without the water contained 35 and 20 grams of flies, respectively, busting the myth.”