Q.  Playing badminton in your backyard on a summer evening is a lot of fun, even if the cheap plastic birdies (shuttlecocks) get easily damaged, causing them to wobble.  Did you know that badminton has been an Olympic sport since 1992?  What kind of birdies do the pros use?

A.  Most competitive badminton tournaments use shuttlecocks that have real feathers, preferably geese feathers and mostly those from the left wing, says Dan Lewis on his “Now I Know” website.  Aerodynamics is the reason.  According to a deputy commissioner of the Badminton World Federation, the feathers from the left and right wings are curved differently:  shuttlecocks made from the left wing will spin clockwise, while those from the right have an undesired, inconsistent spin.  Mixing the feathers from both wings is also undesirable, since it will cause the shuttlecock to wobble.

But there aren’t a lot of featherless geese out there, the commissioner adds.  “The geese are bound for butcher shops or being plucked for down pillows and jackets.  If the feathers of their left wings weren’t used for shuttlecocks, they’d be used for something else, or just thrown away.”

Now you know “badminton’s sinister secret,” as Lewis titled his entry, explaining that the word “sinister” comes from the same Latin word, which meant “left” or “on the left side.” 

Q.  It can resist a crushing pressure roughly equal to the weight of an African bull elephant balanced on a coin, yet a very weak pulling force can tear it apart.  The Romans were the first to make it, and today its presence can be seen everywhere.  What is it?

A.  It’s concrete.  Rome’s Pantheon, completed in 126 C.E., still spans a greater distance than any other structure made of non-reinforced concrete, say Vaclav Smil in “IEEE Spectrum” magazine.  Concrete’s components are cement (7-15%), water (14-21%) and sand and gravel (60-75%).  The weakness of concrete, as noted before, can be offset by reinforcement, and before the end of the 19th century, steel reinforcement was common in construction: in freeways, paved roads, airport runways and parking lots.  Today, notable concrete structures include 65.5 million metric tons in the Three Gorges Dam in China; 21.7 million metric tons for the Grand Coulee Dam in Washington State; and 0.11 million metric tons for Burj Khalifa Tower, the world’s tallest building, in Dubai, United Arab Emirates. 

In 1985, China became the world’s largest producer of cement (comprising up to 15% of concrete), and its output now accounts for nearly 60% of the global total.  Consider that “in 2017 and 2018, China made slightly more cement… than the U.S had made throughout the entire 20th century.”

Q.  Great white sharks are perhaps the most widely feared predators in the ocean.  So why did “Scientific American” magazine label them “scaredy-sharks”?

A.  Because they may have something to fear from orcas, also known as killer whales, says the magazine’s Jason Goldman.  According to research scientist Salvador Jorgensen, who has spent more than 15 years studying great white sharks near California’s coast, something unusual happened in 2009:  all 17 of them that were swimming around the Farallon Islands simultaneously departed in a matter of hours, when normally it would take weeks or months.  As Jorgensen and colleagues reported, “Great whites have been seen abandoning this prime feeding area when killer whales come too close for comfort-—even if the mammals are simply passing through for a few hours.”  And the sharks stay away for the entire season.

While it’s not known how the sharks detect the orcas, the researchers suggest that most likely the sharks “were able to smell something in the water that alerted them,” perhaps sniffing out the orcas themselves or some chemical cue from another stressed-out shark after an encounter.

The fact is that sharks have existed for 450 million years, and, Jorgensen says, “For sharks to have survived and thrived in our ocean for so long, they have their bag of tricks….  One of those tricks is knowing when to fold.”