Author: Bethany Brookshire / Source: Science News for Students
A bowl of rice cereal might seem like it has nothing in common with a huge rock dam or an Antarctic ice sheet. But look a little closer.
When puffed rice is poured into milk and pressed down, liquid creeps into the cereal. The rice then sinks into the liquid with a large crash. At this point, a slow creep begins again. Those crashes — called ricequakes — happen at regular, predictable times, a new study finds. And the snap, crackle and pop of Rice Krispies soaking in milk can help scientists understand how larger things fall apart, such as huge ice sheets or heaps of rocks.Itai Einav works in Australia at the University of Sydney. Technically, he is an engineer who studies granular materials. And those can be anything from rocks and sand to flour. But these days, you might call him a cereal scientist. “I worked for several years on dry Rice Krispies with a colleague,” he explains.
They did a series of studies, just looking at how it crushes. And then, they realized, “There was a connection to rocks.” The patterns that emerge when you crush the cereal, he says, “are strikingly similar.”
Science with cereal alone will soon run dry, however. So he and Francois Guillard poured puffed rice cereal into a tube filled with water or milk. (Puffed rice cereal is called Rice Krispies in the United States but Rice Bubbles in Australia.) The pair then added a weight on top. At 3 kilograms (6.6 pounds), that weight was about as heavy as a very thick book. “We know what happens when you add milk without pressure; everyone’s done it at home,” Einav says. Pressing down on the cereal would better imitate a heavy rockfill dam, he and Guillard suspected.
Those dams are large hills of rocks and dirt. They’re cheap to make because they don’t need concrete or other expensive materials. Dirt and rocks can be found anywhere. What’s more, these dams won’t crack — as concrete might — when an earthquake hits. Rockfill dams are important structures. They hold back water to create big reservoirs. Controlled spills of water from some of them provide electrical power. Other dams might keep chemical wastes from mines or other operations from spilling into the environment.
But unlike dams made of concrete (like the Hoover Dam), those made from rocks and earth have holes. Even the most solid rocks have tiny, tiny holes in them, Einav explains. “Rocks without holes…
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