![]() ![]() In that case, you are the excess charge's exit route.īut why all the buildup? It's unclear. Alternatively, they can occur when static electricity builds up on something else a doorknob, say which you then touch. What we know is this: They occur when an excess of either positive or negative charge builds up on the surface of your body, discharging when you touch something and leaving you neutralized. Static shocks are as mysterious as they are unpleasant. Static buildup makes hair stand on end, as positively charged hairs repel each other. It's just a feature of the universe, and the mathematical explanations are just attempts of getting through the 'homework assignment' of nature and getting the answers," Walker told Life's Little Mysteries. Physicists wonder: why do particles radiate magnetic fields, what are magnetic fields, and why do they always align between two directions, giving magnets their north and south poles? "We just observe that when you make a charged particle move, it creates a magnetic field and two poles. Though physicists have come up with a theory called " quantum mechanics" that very accurately explains the behavior of particles including their magnetism there's no way to intuitively understand what the theory really means. Unfortunately, trying to understand magnetism on a deeper level is essentially impossible. This exerts a force on other magnetic objects, either attracting or repelling them depending on the direction of their own magnetic fields. (This is why the electrons in your body don't cause you to stick to your fridge when you walk by it.) But when the magnetic fields all the electrons in an object align in the same direction, as occurs in many metals (and, obviously, in magnets), a net magnetic field is generated. Normally in matter, the magnetic fields of electrons point in different directions, canceling each other out. Jearl Walker, a physics professor at Cleveland State University and coauthor of the widely used textbook "Fundamentals of Physics" (Wiley, 8th Edition 2007), explains that magnetic fields naturally radiate outward from the electrically charged particles that make up atoms especially electrons. Magnets: pretty weird, huh? What's up with them? ![]() ![]() (Image credit: Kabl00ey | Creative Commons) When two pieces of cereal touch, their two dents become one, and, resting in it, they stick together. For this reason, pieces of the cereal near the edge float upward along this curve, appearing as if they're clinging to the edge.Īlso because of surface tension, cereal floating in the middle of your bowl dents the milk's surface, creating a dip in it. Because water molecules in the milk are attracted to glass, the milk's surface curves upward around the bowl's edge. Surface tension makes the milk's surface cave in slightly in the middle of the bowl. The Cheerios Effect, they proved, results from the geometry of a liquid's surface. Dubbed the Cheerios Effect by scientists, this clumping phenomenon applies to anything that floats, including fizzy soda bubbles and hair particles in water after a morning shave.ĭominic Vella, a graduate student now at Cambridge University, and Lakshminarayanan Mahadevan, a mathematician from Harvard University, were the first to explain the effect in terms of simple physics, which they did in a 2005 paper. You may or may not have pondered why your breakfast cereal tends to clump together or cling to the sides of a bowl of milk. "The physics of foam is poorly understood," Durian told NASA Science. However, no formula exists for predicting exactly how stiff or oozy a foam will be based on the size of its bubbles or the amount of liquid it contains. The gas in the foam separates the liquid to form a matrix of tiny bubbles, and if the bubbles' liquid walls are rigid enough, the foam can sometimes keep its shape. Somehow these add up to give them certain traits of solids, too. For starters, consider this: Is whipped cream a solid, a liquid, or a gas?Īccording to Douglas Durian, a professor of physics at UCLA, foams are typically 95 percent gas and 5 percent liquid. We encounter foam so often that few of us step back and fully appreciate how weird the stuff really is. Had a bubble bath today? Maybe not but you've probably shaved, washed dishes, had a latte or beer, or, if you're lucky, eaten a piece of pie topped with a puff of whipped cream. Shaving cream is but one example of a mysterious substance called foam. ![]()
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