How ’bout them nuts?
X-ray CT scans reveal that jostling a field of blended nuts nudges rectangular Brazil nuts to level extra vertically, permitting the cumbersome nuts to relaxation on high as smaller ones sink to the underside, Maria Temming reported in “How physics helps Brazil nuts come out on high” (SN: 6/5/21, p. 4).
Reader Charvak Kant requested if this phenomenon, referred to as the Brazil nut impact, applies to things of all shapes — together with spheres whose orientations wouldn’t change.
Form impacts the Brazil nut impact, however precisely how remains to be unclear, says imaging scientist Parmesh Gajjar of the College of Manchester in England. It is extremely troublesome to experimentally look at mixtures of objects, Gajjar says, however measurement does strongly affect how particles segregate. Even spheres of various sizes in a mix will separate. Actually, the very first examine to make use of the phrase “Brazil nut impact,” revealed in Bodily Evaluation Letters in 1987, was performed on spherical objects, he says.
Chaotic clocks
As a clock turns into extra correct, it generates extra dysfunction, Emily Conover reported in “Strict timekeeping creates entropy” (SN: 6/5/21, p. 13).
Reader Steve Comins puzzled why an correct clock would emit extra dysfunction than an inaccurate clock that ticks too quick.
In brief, consistency is essential, Conover says. Within the context of the story, an inaccurate clock refers to 1 whose ticks are erratically spaced, she says. Some ticks might come quicker and a few slower than they need to, so you possibly can’t predictably inform time. However a clock that ticks persistently quicker or persistently slower than regular may nonetheless be correct, so long as you determine the speed at which it’s ticking.
For instance, a clock that persistently ticks twice in a single second may nonetheless precisely inform time; you’d simply must depend every tick as a half-second. Such a fast-ticking clock would possible emit extra entropy than a traditional clock, however it will even be extra exact, in accordance with the researchers’ outcomes, Conover says.
Fluid definitions
A wave in one among Saturn’s rings reveals that the planet’s core is unfold out and bloated with hydrogen and helium, Ken Croswell reported in “Saturn’s coronary heart is fuzzy and diffuse” (SN: 6/5/21, p. 9).
Saturn’s immense gravity squeezes a lot of the planet’s hydrogen and helium, which exist as gases on Earth, right into a fluid, Croswell reported. Reader Ken Koutz questioned using the time period “fluid,” on condition that gases are already thought-about fluids.
Whereas a fluid is usually a fuel or a liquid, physicists usually use the time period to confer with supercritical states, by which distinct fuel and liquid phases are blurred, story editor Chris Crockett says. “That’s precisely what is believed to occur deep inside big planets reminiscent of Saturn,” he says. “The fluid there’s neither fuel nor liquid, strictly talking, nevertheless it nonetheless has fluid properties.”
Placing the squeeze on useless stars
Essentially the most large neutron star identified has a surprisingly giant diameter, suggesting that the matter inside it’s much less squeezable than anticipated, Emily Conover reported in “Neutron stars will not be so squishy” (SN: 6/5/21, p. 8).
Reader Jim Barr wished to know what “squeezable” means within the context of neutron stars.
This time period refers to how a lot a cloth compresses below strain, Conover says. For instance, in case you squeeze a metal ball in your hand, it received’t get considerably smaller. However in case you do the identical with a foam ball, it should. And the more durable you squeeze the froth ball, the smaller it should get.
For neutron stars, the query is whether or not the core will get smaller when squeezed by gravity. The extra large a star, the higher the gravitational strain. So whether or not a extra large star is larger, smaller or the identical measurement as a much less large one is determined by whether or not the star’s core compresses or not.
