CLOSE
Getty Images
Getty Images

Can a Foil Hat Keep People From Reading Your Thoughts?

Getty Images
Getty Images

Let’s say that the conspiracy theorists are right. Let’s say some malevolent group—the government, powerful corporations, extraterrestrials—really is trying to read and/or control the thoughts of the Average Joe with radio waves. Would the preferred headgear of the paranoid, a foil helmet, really keep The Man and alien overlords out of our brains?

The scientific reasoning behind the foil helmet is that it acts as a Faraday cage, 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 sometimes these enclosures are actual cages, they come in many forms, and most of us have probably dealt with one type or another. Elevators, the scan rooms that MRI machines sit in, “booster bags” that shoplifters sometimes use to circumvent electronic security tags, cables like USB or TV coaxial cables, and even the typical household microwave all provide shielding as Faraday cages.

While the underlying concept is good, the typical foil helmet fails in design and execution. An effective Faraday cage fully encloses whatever it's shielding, but a helmet that doesn’t fully cover the head doesn’t fully protect it. If the helmet is designed or worn with a loose fit, radiofrequency electromagnetic radiation can still get up underneath the brim from below and reveal your innermost thoughts to the reptilian humanoids or the Bilderberg Group.

Opposite Effect

In 2005, a group of MIT students, prodded by "a desire to play with some expensive equipment,” tested the effectiveness of foil helmets at blocking various radio frequencies. Using two layers of Reynolds aluminum foil, they constructed three helmet designs, dubbed the Classical, the Fez, and the Centurion, and then looked at the strength of the transmissions between a radio-frequency signal generator and a receiver antenna placed on various parts of their subjects’ bare and helmet-covered heads.

The helmets shielded their wearers from radio waves over most of the tested spectrum (YouTube user Mrfixitrick likewise demonstrates the blocking power of his foil toque against his wireless modem) but, surprisingly, amplified certain frequencies: those in the 2.6 Ghz (allocated for mobile communications and broadcast satellites) and 1.2 Ghz (allocated for aeronautical radionavigation and space-to-Earth and space-to-space satellites) bands.

While the MIT guys’ tongue-in-cheek conclusion—“the current helmet craze is likely to have been propagated by the Government, possibly with the involvement of the FCC”—maybe goes a few steps too far, their study at least shows that foil helmets fail at, and even counteract, their intended purpose. That, or the students are aliens or government agents who fabricated these results in an effort to get you to take your perfectly functional helmet off…

nextArticle.image_alt|e
iStock
arrow
Big Questions
Are There Number 1 Pencils?
iStock
iStock

Almost every syllabus, teacher, and standardized test points to the ubiquitous No. 2 pencil, but are there other choices out there?

Of course! Pencil makers manufacture No. 1, 2, 2.5, 3, and 4 pencils—and sometimes other intermediate numbers. The higher the number, the harder the core and lighter the markings. (No. 1 pencils produce darker markings, which are sometimes preferred by people working in publishing.)

The current style of production is profiled after pencils developed in 1794 by Nicolas-Jacques Conté. Before Conté, pencil hardness varied from location to location and maker to maker. The earliest pencils were made by filling a wood shaft with raw graphite, leading to the need for a trade-wide recognized method of production.

Conté’s method involved mixing powdered graphite with finely ground clay; that mixture was shaped into a long cylinder and then baked in an oven. The proportion of clay versus graphite added to a mixture determines the hardness of the lead. Although the method may be agreed upon, the way various companies categorize and label pencils isn't.

Today, many U.S.  companies use a numbering system for general-purpose, writing pencils that specifies how hard the lead is. For graphic and artist pencils and for companies outside the U.S., systems get a little complicated, using a combination of numbers and letters known as the HB Graphite Scale.

"H" indicates hardness and "B" indicates blackness. Lowest on the scale is 9H, indicating a pencil with extremely hard lead that produces a light mark. On the opposite end of the scale, 9B represents a pencil with extremely soft lead that produces a dark mark. ("F" also indicates a pencil that sharpens to a fine point.) The middle of the scale shows the letters and numbers that correspond to everyday writing utensils: B = No. 1 pencils, HB = No. 2, F = No. 2½, H = No. 3, and 2H = No. 4 (although exact conversions depend on the brand).

So why are testing centers such sticklers about using only No. 2 pencils? They cooperate better with technology because early machines used the electrical conductivity of the lead to read the pencil marks. Early scanning-and-scoring machines couldn't detect marks made by harder pencils, so No. 3 and No. 4 pencils usually resulted in erroneous results. Softer pencils like No. 1s smudge, so they're just impractical to use. So No. 2 pencils became the industry standard.

nextArticle.image_alt|e
WANG ZHAO/AFP/Getty Images
arrow
Big Questions
What Are Curlers Yelling About?
WANG ZHAO/AFP/Getty Images
WANG ZHAO/AFP/Getty Images

Curling is a sport that prides itself on civility—in fact, one of its key tenets is known as the “Spirit of Curling,” a term that illustrates the respect that the athletes have for both their own teammates and their opponents. But if you’re one of the millions of people who get absorbed by the sport once every four years, you probably noticed one quirk that is decidedly uncivilized: the yelling.

Watch any curling match and you’ll hear skips—or captains—on both sides barking and shouting as the 42-pound stone rumbles down the ice. This isn’t trash talk; it’s strategy. And, of course, curlers have their own jargon, so while their screams won’t make a whole lot of sense to the uninitiated, they could decide whether or not a team will have a spot on the podium once these Olympics are over.

For instance, when you hear a skip shouting “Whoa!” it means he or she needs their teammates to stop sweeping. Shouting “Hard!” means the others need to start sweeping faster. If that’s still not getting the job done, yelling “Hurry hard!” will likely drive the point home: pick up the intensity and sweep with downward pressure. A "Clean!" yell means put a brush on the ice but apply no pressure. This will clear the ice so the stone can glide more easily.

There's no regulation for the shouts, though—curler Erika Brown says she shouts “Right off!” and “Whoa!” to get her teammates to stop sweeping. And when it's time for the team to start sweeping, you might hear "Yes!" or "Sweep!" or "Get on it!" The actual terminology isn't as important as how the phrase is shouted. Curling is a sport predicated on feel, and it’s often the volume and urgency in the skip’s voice (and what shade of red they’re turning) that’s the most important aspect of the shouting.

If you need any more reason to make curling your favorite winter sport, once all that yelling is over and a winner is declared, it's not uncommon for both teams to go out for a round of drinks afterwards (with the winners picking up the tab, obviously). Find out how you can pick up a brush and learn the ins and outs of curling with our beginner's guide.

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

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios