Does a Refrigerator Make a Good Faraday Cage?

The other week, the New York Times reported that NSA whistleblower Edward Snowden was understandably cautious about planning his departure from Hong Kong to Russia (emphasis mine):

“It was a cloak-and-dagger affair. Mr. Snowden wore a cap and sunglasses and insisted that the assembled lawyers hide their cellphones in the refrigerator of the home where he was staying, to block any eavesdropping. Then began a two-hour conversation during which Mr. Snowden was deeply dismayed to learn that he could spend years in prison without access to a computer during litigation over whether he would be granted asylum here or surrendered to the United States.

Wait. What? Why are the cellphones getting chilled? Snowden’s idea, presumably, was that the refrigerator would act as a Faraday cage. As I explained last year when talking about the effectiveness of tin foil helmets, a Faraday cage is an enclosure made up of a conducting material that shields its interior from external electrostatic charges and electromagnetic radiation by distributing them around its exterior and dissipating them. While these enclosures are sometimes actual cages, they come in many forms, and most of us have probably dealt with one type or another. The scan rooms that MRI machines sit in and the shielding on USB cables, for example, both provide protection as Faraday cages. Inside such a cage, signals to and from these lawyers’ cellphones would be blocked, preventing them from being used to surveil the meeting.

In theory, a sturdy metal fridge should make a good Faraday cage. In practice, some fridges don’t really cut a cell phone off from the rest of the world. Make magazine writer Michael Colombo tried it out with his home refrigerator, and was able to make a call to a phone inside of it. He had better results with a metal cocktail shaker.

I put my fridge to the test, too, and got the same result. Calls and data transmissions went right through. I have a glass cocktail shaker, so that's not an option for me if I'm trying to stay hidden. I wondered if there was a decent kitchen Faraday cage available to people like me, or the poor souls who have no cocktail shaker at all.

I lurked on some survivalist message boards for a while (not an activity I can recommend) and learned that a lot of doomsday hobbyists plan on relying on their microwave to protect their electronics if the government/aliens/New World Order tries to mess with them with an electromagnetic pulse. This makes sense, since, unlike a fridge, a microwave oven is actually designed specifically to shield the electromagnetic radiation of microwaves and keep them from getting out of the appliance. If electromagnetic radiation can’t get out, then it shouldn’t be able to get in either.

Sure enough, calls and data sent to my phone while it sat in my old GE microwave never went through. I could see it sitting in there, but there was no ring, no alerts. When I pulled it out, there was no missed call notification, either. So, the next time you need to keep prying eyes and ears away from your phone, your best bet seems to be tossing it in the microwave or a (metal) cocktail shaker. Just don’t forget about it when you heat up some leftovers or make a Manhattan.

Big Questions
What is Mercury in Retrograde, and Why Do We Blame Things On It?

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding for the first time this year on Friday, March 23. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?


Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.


Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the Sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the Sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the Sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the Sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This story originally ran in 2017.

Big Questions
What Is Fair Trade?

What is fair trade?

Shannon Fisher:

Fair trade is a system of manufacturing and purchasing intended to:

1) level the economic playing field for underdeveloped nations; and

2) protect against human rights abuses in the Global South.

Fair trade farmers are guaranteed fair market prices for their crops, and farm workers are guaranteed a living wage, which means workers who farm fair trade products and ingredients are guaranteed to earn enough to support their families and comfortably live in their communities. There are rules against inhumane work practices. Fair trade farming organizations are monitored for a safe work environment, lack of discrimination, the freedom to organize, and strict adherence to child labor laws. Agrochemicals and GMOs are also forbidden. If these rules are not followed, a product will not receive fair trade certification.

The quality of life in many communities producing fair trade-certified goods is greatly improved. Sometimes, farming communities are given profit sharing from the companies that source their ingredients, and those profits go to improving the community as a whole—be it with a library, medical facilities, town infrastructure, or opening small businesses to support the residents. A major goal of fair trade is to help foster sustainable development around the globe. By helping farming communities in third-world countries, the economy of the entire region gets a boost.

This post originally appeared on Quora. Click here to view.


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