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Key concepts Energy Gravity Physics Sports Introduction Playing basketball can be hard work. Players not only have to run around the court, but just dribbling the basketball takes some serious effort, too. Have you ever wondered why that is? The challenge has to do with how the basketball bounces. When the ball hits the court, its bounce actually loses momentum by transferring some of its energy—into a different form. This means that to keep the ball bouncing to the same height, players must continually put energy into the ball with each bounce....

The first results from a massive project to exhaustively catalogue all the functions of the human genome reveal a hotbed of activity in the gaps between genes. An international consortium of researchers sifted through 1 percent of the genome looking for pieces of DNA that are copied by the cell or help to control gene activity. The results indicate that most DNA is copied into molecules of RNA, including the long stretches between genes, and that genes overlap and interact with each other much more than researchers previously believed....

If you sometimes start your morning with a frothy cappuccino and finish off the evening with a heady glass of beer, then your day opens and closes with one of the most scientifically intriguing kinds of food: the edible foam. There are deep mathematical mysteries in these interlocked bubbles, and recently they have also become one of the most fertile areas for culinary innovation. Top-ranked chef Ferran Adrià of elBulli in Catalonia, Spain, began experimenting with culinary foams in the mid-1990s in his quest to present diners with new and unexpected culinary experiences....

WIND RIVER RANGE, Wyo. — Here at the roof of the Continental Divide, one of the Rocky Mountains’ largest glaciers is in retreat. A new world is emerging in the wake of the receding ice. In a vast, glacially carved basin, where towering spires of granite dominate the skyline, a small colony of stunted Engelmann spruce has taken up residence in a pile of rocky debris, some 500 feet above the tree line....

Identifying genius is a dicey venture. Consider, for example, this ranking of “The Top 10 Geniuses” I once stumbled across on Listverse.com. From first to last place, here are the honorees: Johann Wolfgang von Goethe, Leonardo da Vinci, Emanuel Swedenborg, Gottfried Wilhelm Leibniz, John Stuart Mill, Blaise Pascal, Ludwig Wittgenstein, Bobby Fischer, Galileo Galilei and Madame de Staël. What about Albert Einstein instead of Swedenborg? Some of the more recently deceased might also deserve this appellation—Stephen Hawking comes to mind....

Naturalists have long noted isolated examples of tree roots boring far down through loose soil and into the unforgiving bedrock below—rare incursions that were deemed a mere curiosity. But in 2013 hydrologist Daniella Rempe probed deep into a northern California hillside and found tree roots extracting substantial amounts of moisture from pores and crannies in the rock, where groundwater had seeped in and become trapped. “We wanted to assess how big of a phenomenon this was,” says Erica McCormick, an ecohydrologist in Rempe’s laboratory at the University of Texas at Austin....

When Scientific American heard from chemist Ray Baughman a year ago, he and his international team of nanotechnologists had taken artificial-muscle technology to the next level. Their innovation relied on spinning lengths of carbon nanotubes into buff yarns whose twisting and untwisting mimicked natural muscles found in an elephant’s trunk or a squid’s tentacles. Now the researchers are reporting a new artificial muscle–building technique that makes their carbon nanotube yarns several times faster and more powerful....

With Thanksgiving kicking the end-of-year travel season into full gear, concerns over air travel safety have predictably resurfaced. The main issues this time surround the Transportation Security Administration’s (TSA) advanced imaging technology (AIT) machines—even though the agency has been rolling out these devices over the past few years—as well as the TSA-administered security pat-downs of passengers who refuse to submit to AIT screening. Controversy has bubbled up this month on a number of fronts....

The notion of an artificial leaf makes so much sense. Leaves, of course, harness energy from the sun to turn carbon dioxide into the carbohydrates that power a plant’s cellular activities. For decades scientists have been working to devise a process similar to photosynthesis to generate a fuel that could be stored for later use. This could solve a major challenge of solar and wind power—providing a way to stow the energy when the sun is not shining and the air is still....

A new genetic analysis of large, inbred Middle Eastern families found that genes linked to a heightened risk of autism are crucial to a child’s ability to learn. A group of scientists, led by a team at Children’s Hospital Boston, has pinpointed six new genes that may contribute to autism, a disorder characterized by asocial behavior, difficulty communicating and repetitive actions that affects an estimated one in 150 children born in the U....

Bear-size beavers, mammoths, horses, camels and saber-toothed cats used to roam North America, but by 11,000 years ago most such large mammals had died off. To this day, experts debate what caused this late Pleistocene extinction: climate change, overhunting by humans, disease—or something else? Eric Scott, curator of paleontology at the San Bernardino County Museum in Redlands, Calif., suggests it was something else: namely, the immigration of bison from Eurasia. Armed with data from his own ongoing excavations as well as from those dating back as far as the 1800s, Scott says that bison appeared in North America as early as 220,000 years ago and spread across the continent throughout the remainder of the Pleistocene, a time when climate change had made food and water scarce....

For more than 2,000 years, chemists, engineers and interested amateurs have been working to build a better concrete. The Romans started the process with their invention of a concrete made from quicklime, ash and pumice that enabled the construction of their fabulous–and long-lasting–architecture and infrastructure. Nearly two millennia later, John Smeaton–the father of civil engineering–improved this basic building material by improving the cement that held it together. Yet despite numerous improvements over subsequent centuries, concrete structures exposed to the worst conditions are not surviving for as long as expected....

We humans aren’t the only ones who want to fit in. Researchers have discovered that chimpanzees, too, preferentially adopt their fellow chimps’ way of doing things. Andrew Whiten of St. Andrews University in Fife, Scotland, and his colleagues studied three groups of captive chimpanzees and the ways in which they assumed different techniques for obtaining food. The first group contained a high-ranking female that had been taught to retrieve food from an apparatus by using a stick to push a blockage away, thus freeing the food item....

In 2005, after NASA’s Deep Impact spacecraft had completed its objective of slamming an impactor probe into the nucleus of Comet Tempel 1, mission scientists began plotting their next move. The spacecraft that had released the probe and documented its cometary collision was intact, with fuel to spare, leaving it well equipped to rendezvous with another comet in the inner solar system. Comets preserve some of the primordial materials from the early solar system, and the rare close look offers planetary scientists a glimpse of conditions that prevailed billions of years ago....

Actress and writer Carrie Fisher, who died earlier this week after suffering a cardiac event on a flight, was not only an entertainment icon, but also a prominent mental health advocate. Fisher was well known for being outspoken about her experiences with drug and alcohol addiction and bipolar disorder, which she was diagnosed with in her early twenties, and she frequently wrote about them in articles and her best-selling 2008 memoir Wishful Drinking (Simon & Schuster)....

Last month Denmark’s biggest energy firm, Ørsted, said wind farms it is proposing for the North Sea will convert some of their excess power into gas. Electricity flowing in from offshore will feed on-shore electrolysis plants that split water to produce clean-burning hydrogen, with oxygen as a by-product. That would supply a new set of customers who need energy, but not as electricity. And it would take some strain off of Europe’s power grid as it grapples with an ever-increasing share of hard-to-handle renewable power....

East Turkana, Kenya—What unnerves Louise Leakey is not so much the banditry on the only supply road or the gun battles among herders who sometimes mistake researchers for their enemies—it’s the goats. When a fossil in the Lake Turkana region in northern Kenya makes its way back to the eroding surface after several million years, it’s just a matter of time before, as Leakey puts it, “a herd of 200 to 600 goats with those little hooves, four apiece, goes straight over it....

How well these natural musicians played together, Krause concludes, says good deal about the health of the environment. He argues that many animals evolved to vocalize in available niches so they can be heard by mates and others of their kind, but noise from human activity—from airplanes flying overhead to rumbling tires on a nearby road—threatens an animal’s reproductive success. Thomas S. Schulenberg, a neotropical bird specialist at Cornell University and one of the authors of The Birds of Peru, agrees that sound is a useful tool for assessing the natural environment....

The first “insurance policy” on record is probably the Codex Hammurabi, circa 1780 B.C., which you can still read in the original at the Louvre Museum in Paris if you are nimble with ancient Sumerian legalese. It avers that shippers whose goods were lost or stolen in transit would be compensated by the state. (How did shippers prove their claims? A sworn declaration before a god was good enough for the king of Babylon....

The earthquake and tsunami that struck Japan last March created an estimated 25 million tons of debris, large amounts of which washed into the ocean. Soon after the disaster, satellites photographed and tracked large mats of wreckage—building parts, boats and household objects—floating off the Japanese coast. Now, according to computer models developed by Nikolai Maximenko and his colleagues at the University of Hawaii and at the U.S. National Oceanic and Atmo­spheric Administration, the detritus is on course to reach the north­western Hawaiian Islands early this year....