This Electric Dipstick Zaps the Pollutants Out of Water

Felice Frankel
Felice Frankel

There’s no such thing as too many good ideas when it comes to making more clean water for our thirsty planet. The latest: a customizable electric filtration device that zaps contaminants clear out of the water. The device’s creators describe it in the journal Energy and Environmental Science.

There are currently three basic types of water filtration processes: membrane filtration, like the type in your water pitcher; electrodialysis; and capacitive deionization. All three methods work quite well, but the first option is expensive and can’t catch small amounts of contamination, and the latter two require lots of electricity to run—all significant obstacles in impoverished regions where resources are already scarce.

So a group of chemical engineers from the U.S. and Germany teamed up to make something better. Their solution is surprisingly simple: a set of electrically charged dipsticks that can target pesticides, chemical waste, and even prescription drugs.

Each dipstick is an electrode coated with what are called Faradaic materials. The coatings can be treated to make them either positively or negatively charged, and to resonate with—and thus zap—specific molecules.


Melanie Gonick/MIT

To test the dipsticks, the researchers immersed them in water contaminated with very low doses of ibuprofen and different types of pesticide. The setup worked beautifully, targeting and eliminating pollutant molecules even at levels as low as a few parts per million.

The new technology is also incredibly energy efficient, requiring so little energy that it could easily be powered by solar panels in remote areas with no other access to electricity.

Matthew Suss of the Technion Institute of Technology was not part of the development team but calls it “highly significant.” Speaking in a statement, he said the technology “…extends the capabilities of electrochemical systems from basically nonselective toward highly selective removal of key pollutants.”

The next challenge will be scaling the device up to treat higher quantities of water outside the lab. “As with many emerging water purification techniques,” Suss added, “it must still be tested under real-world conditions and for long periods to check durability."

This 'Time-Traveling Illusion' Is Designed to Trick Your Brain

A team of researchers from the California Institute of Technology (Caltech) have designed an illusion that might trick your brain into seeing things that aren’t there, the New Atlas reports.

Dubbed the Illusory Rabbit, it provides instructions that are simple enough to follow. Start playing the YouTube video below and look at the cross in the middle of the screen while also watching for flashes that appear at the bottom of the screen. Most importantly, you’ll want to add up the number of flashes you see throughout the video. (And make sure your volume is up.)

We don’t want to spoil the fun, so before we explain the science of how it works, check out the video and try it for yourself.

Did you see three flashes paired with three beeps? You’re not alone. This is due to a phenomenon called postdiction, which is a little like the opposite of prediction. According to a paper outlining these findings in the journal PLOS ONE, postdiction occurs when the brain processes information retroactively [PDF]. This occurs in such a way that our perception of earlier events is altered by stimuli that come later. In this case, you might think you missed the flash paired with the second of the three beeps, so your mind goes back and tries to make sense of the missing information. That's why you may see an “illusory flash” in the middle of the screen, sandwiched between the two real flashes.

For this reason, the researchers call the mind trick a “time-traveling illusion across multiple senses” (in this case, vision and hearing). It’s successful because the beeps and flashes occur so rapidly—in less than one-fifth of a second. The senses essentially get confused, and the brain tries to fill in the gaps retroactively.

"Illusions are a really interesting window into the brain," the paper’s first author, Noelle Stiles, said in a statement. "By investigating illusions, we can study the brain's decision-making process.” Researchers wanted to find out how the brain “determines reality” when a couple of your senses (in this case, sight and hearing) are bombarded with noisy and conflicting information. When the brain isn’t sure of what’s going on, it essentially makes up information.

“The brain uses assumptions about the environment to solve this problem,” Stiles said. “When these assumptions happen to be wrong, illusions can occur as the brain tries to make the best sense of a confusing situation. We can use these illusions to unveil the underlying inferences that the brain makes."

[h/t New Atlas]

How Did 6 Feet Become the Standard Grave Depth?

iStock
iStock

It all started with the plague: The origins of “six feet under” come from a 1665 outbreak in England. As the disease swept the country, the mayor of London literally laid down the law about how to deal with the bodies to avoid further infections. Among his specifications—made in “Orders Conceived and Published by the Lord Mayor and Aldermen of the City of London, Concerning the Infection of the Plague”—was that “all the graves shall be at least six feet deep.”

The law eventually fell out of favor both in England and its colonies. Modern American burial laws vary from state to state, though many states simply require a minimum of 18 inches of soil on top of the casket or burial vault (or two feet of soil if the body is not enclosed in anything). Given an 18-inch dirt buffer and the height of the average casket (which appears to be approximately 30 inches), a grave as shallow as four feet would be fine.

A typical modern burial involves a body pumped full of chemical preservatives sealed inside a sturdy metal casket, which is itself sealed inside a steel or cement burial vault. It’s less of a hospitable environment for microbes than the grave used to be. For untypical burials, though—where the body isn’t embalmed, a vault isn’t used, or the casket is wood instead of metal or is foregone entirely—even these less strict burial standards provide a measure of safety and comfort. Without any protection, and subjected to a few years of soil erosion, the bones of the dearly departed could inconveniently and unexpectedly surface or get too close to the living, scaring people and acting as disease vectors. The minimum depth helps keep the dead down where they belong.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article originally appeared in 2012.

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