Readers ask about buoyancy, Stonehenge sounds and extra

Rock the boat

Scientists made a toy boat float the wrong way up on the underside of a layer of levitating liquid, Maria Temming reported in “Toy boats defy gravity by floating the wrong way up” (SN: 9/26/20, p. 32).

“I used to be fairly intrigued by the upside-down boat. The reason of buoyancy versus gravity does recommend an equilibrium for the upside-down boat, nevertheless it appears to be unstable in concept,” reader David Edmonston wrote. “If the upside-down boat have been pushed upward ever so barely, then its buoyancy ought to improve, making the boat rise to the highest of the liquid layer,” Edmonston wrote. “If it have been pushed downward, then its buoyancy ought to lower, permitting it to fall beneath the underside of the levitated liquid. That might be an unstable equilibrium, like standing a pencil on its level. Is there extra to the reason? Is there floor rigidity concerned? Upward drive from the levitation?” he requested.

The boat does exist in an unstable equilibrium, Temming says. “Shaking the container holding the boat and liquid helps the upside-down boat keep a gentle place on the underside of the liquid layer,” she says. “As a result of the boat is consistently shaking up and down as properly, its personal vertical vibrations cancel out any exterior jostling that will knock the boat off its float. Extra large boats require stronger shaking to withstand being knocked all the way down to the underside of the container or as much as the highest of the liquid layer.”

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Spooky sound results

A scale mannequin of Stonehenge revealed that the whole construction would have amplified speech and improved musical sounds for individuals inside it, Bruce Bower reported in “Stonehenge enhanced sounds inside” (SN: 9/26/20, p. 14).

“I’ve all the time discovered Stonehenge very attention-grabbing. It’s in the midst of fields, however a busy street passes it a couple of half a mile or so away.… You get a bizarre thrill seeing it loom up out of the mist as you drive alongside,” reader Michelle Reeve wrote. “One other bizarre acoustic impact is that though the street is seen from the monument … surprisingly you can not hear the visitors. Sound usually carries properly over open floor,” Reeve wrote. “It gives the look of a ghost street from one other dimension. A spooky impact!”

Vitality issues

Spacetime ripples revealed that two black holes merged to type the primary definitive instance of a midsize black gap, Emily Conover reported in “Midsize black holes actually do exist” (SN: 9/26/20, p. 7).

Eight photo voltaic plenty’ price of vitality was carried away by gravitational waves throughout the merger. Reader Jonathan Lis questioned if matter was transformed into that vitality.

Matter particles aren’t being transformed into vitality on this case, Conover says. As an alternative, different types of vitality are remodeled into the gravitational wave vitality. “The orbiting black holes have each kinetic and potential vitality. It’s that vitality that will get transformed into gravitational waves,” she says. As a result of vitality and mass are equal usually relativity, which means the overall mass of the system decreases when the black holes merge.

Life story

Clumps of micro organism uncovered to the cruel situations of outer house may be capable to climate a visit between Earth and Mars, Jonathan Lambert reported in “Micro organism can survive for years in house” (SN: 9/26/20, p. 10).

Reader Daniel Jameson questioned if such floating clumps of microbes may have seeded early Earth with life.

That concept is one in every of many theories for the way life on Earth started, Lambert says. Whereas there’s no direct proof that life descended from otherworldly microbes, amino acids and sugars have been present in outer house and inside meteorites on Earth. That means house rocks may have delivered these and different essential elements for all times to the planet. One other concept is that early Earth shaped the elements, and ultimately life, by itself (SN: 9/26/20, p. 22).

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