The Reason Why Objects in a Car’s Side-View Mirror Are Closer Than They Appear

aydinozcanbaz/iStock via Getty Images
aydinozcanbaz/iStock via Getty Images

“Objects in mirror are closer than they appear.” It's a warning you see in basically every car, but why can't passenger-side mirrors display objects accurately? Well, it's actually a careful design choice made with safety in mind.

The way we see things is dependent on how light reflects off objects around us. An object's color, texture, shape, and other characteristics influence the direction and intensity of light that bounces off them. If the objects are reflected off an intermediate object, like a mirror, our perception of the original object may be distorted.

The shape of the mirror also makes a difference in our perception. In the U.S., passenger-side mirrors are convex (curved slightly outward), whereas driver-side mirrors are flat. A convex mirror placed on the passenger side reduces the driver's blind spots on that side of the vehicle by presenting a wider field of view, but it also makes other cars appear farther away due to a slight distortion caused by the shape. The flatter mirror on the driver’s side produces a more accurate depiction of what’s behind the car with a more narrow field of view, since light bounces off in the same direction that it hits the mirror and doesn't distort the reflection of the object.

When the two mirrors' reflections are combined in the driver's point of view, drivers have the ability to both see wider areas on the passenger side while keeping their eyes (mainly) on the road. The flat-convex combo has been the U.S. standard for years, though the U.S. Department of Transportation is looking into the safety benefits of two convex mirrors, which European cars usually sport.

For now, always remember to check your mirrors frequently, and look over your shoulder before you change lanes. (Don't forget your turn signal!)

The Ingenious Reason Medieval Castle Staircases Were Built Clockwise

Shaiith/iStock via Getty Images
Shaiith/iStock via Getty Images

If you’re a fan of Game of Thrones or medieval programs in general, you’re probably familiar with action-packed battle scenes during which soldiers storm castles, dodge arrows, and dash up spiral staircases. And, while those spiral staircases might not necessarily ascend clockwise in every television show or movie you’ve watched, they usually did in real life.

According to Nerdist, medieval architects built staircases to wrap around in a clockwise direction in order to disadvantage any enemies who might climb them. Since most soldiers wielded swords in their right hands, this meant that their swings would be inhibited by the inner wall, and they’d have to round each curve before striking—fully exposing themselves in the process.

Just as the clockwise spiral hindered attackers, so, too, did it favor the castle’s defenders. As they descended, they could swing their swords in arcs that matched the curve of the outer wall, and use the inner wall as a partial shield. And, because the outer wall runs along the wider edge of the stairs, there was also more room for defenders to swing. So, if you’re planning on storming a medieval castle any time soon, you should try to recruit as many left-handed soldiers as possible. And if you’re defending one, it’s best to station your lefties on crossbow duty and leave the tower-defending to the righties.

On his blog All Things Medieval, Will Kalif explains that the individual stairs themselves provided another useful advantage to protectors of the realm. Because the individual steps weren’t all designed with the same specifications, it made for much more uneven staircases than what we see today. This wouldn’t impede the defenders, having grown accustomed to the inconsistencies of the staircases in their home castle, but it could definitely trip up the attackers. Plus, going down a set of stairs is always less labor-intensive than going up.

Staircase construction and battle tactics are far from the only things that have changed since the Middle Ages. Back then, people even walked differently than we do—find out how (and why) here.

[h/t Nerdist]

The Reason Queen Elizabeth II Demands Her Ice Cubes Be Round

The Queen makes a toast with King Willem-Alexander of The Netherlands during a State Banquet at Buckingham Palace in October 2018.
The Queen makes a toast with King Willem-Alexander of The Netherlands during a State Banquet at Buckingham Palace in October 2018.
Yui Mok, WPA Pool/Getty Images

Whether you prefer it crushed, cubed, or cylindrical (complete with a straw-sized hole through the center), you probably have an opinion about which type of ice is the best. As it turns out, so does Queen Elizabeth II.

According to The Independent, the 93-year-old monarch requests that her drinks contain round ice, rather than the more traditional cubes. As Karen Dolby, author of the upcoming Queen Elizabeth II’s Guide to Life, told The Sun, the reason is because balls of ice don’t clink quite as much in the glass—possibly because spheres have smaller surface areas than cubes for any given volume.

Dolby also revealed that the Queen’s ice specifications don’t just apply to her own beverages; she insists that all drinks in her residences be served with round ice. We don’t know for sure if that included the private staff bar that used to be located in Buckingham Palace, but it definitely wasn’t shut down because of a few loud ice cubes.

While promoting his book We Are Amused in 2010, unofficial royal biographer Brian Hoey told ABC News that the Queen detests the noise of ice clinking so much that Prince Philip actually created an ice machine to produce tiny, quieter balls of ice, though that hasn’t been confirmed by any official royal sources.

The Queen might not need ice at all for several beverages she’s been known to enjoy, including tea, champagne, and wine, but she does need it for her drink of choice—gin mixed with Dubonnet, which she prefers on the rocks.

Wondering what else you don’t know about the long-reigning Queen of England? Find out 25 more fascinating facts here.

[h/t The Independent]

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