Why Peanuts 'Dance' When Dropped in Beer
2023-06-19
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1When peanuts are dropped into a glass of beer, they sink to the bottom before floating up and "dancing" in the glass.
2Scientists investigated this process in a study involving the alcoholic drink beer.
3It appeared recently in the publication Royal Society Open Science.
4The scientists say the research helps them understand mineral extraction or bubbling magma in the layer of Earth called the crust.
5Brazilian researcher Luiz Pereira is the study's lead writer.
6He told the French news agency AFP that he first had the idea when passing through Argentina's capital Buenos Aires to learn Spanish.
7It was a "bartender thing" in the city to take a few peanuts and drop them into beers, Pereira said.
8Because the peanuts are more dense than the beer, they first sink to the bottom of the glass.
9Then each peanut becomes what is called a "nucleation site."
10Hundreds of tiny bubbles of carbon dioxide form on their surface.
11The bubbles act as flotation devices that carry the peanuts upward.
12"The bubbles prefer to form on the peanuts rather than on the glass...," said Pereira, a researcher at Germany's Ludwig Maximilian University of Munich.
13When the bubbles reach the surface, they burst.
14The peanuts sink again before newly formed bubbles send the peanuts up again.
15Like a dance movement, the peanuts continue sinking and floating until the carbon dioxide runs out, or someone drinks the beer.
16In the experiments, the team of researchers in Germany, Britain and France examined how peanuts acted in what they called the "beer-gas-peanut system."
17They found the larger the "contact angle" between the curve of an individual bubble and the surface of the peanut, the more likely it would grow.
18But it cannot grow too much - less than 1.3 millimeters across is best, the study said.
19Pereira said he hoped that "by deeply researching this simple system, which everyone can grasp, we can understand a system" that would be useful for industry or explaining natural processes.
20For example, he said the flotation process was similar to the one used to separate iron from ore.
21Air is injected into a mixture in which a mineral, such as iron, "will rise because bubbles attach themselves more easily to it, while other (minerals) sink to the bottom," he said.
22The same process could also explain why volcano scientists find that the mineral magnetite rises to higher layers in Earth's crust than would be expected.
23Like peanuts, magnetite is more dense and should sit at the bottom.
24But the researchers suggest, a high contact angle causes gas bubbles that carry the mineral up through the magma.
25Science is never settled, especially when beer is involved.
26So, Pereira said the scientists hope to create a better model of the dancing peanut action by continuing to experiment with "different peanuts and different beers."
27I'm Dorothy Gundy.
1When peanuts are dropped into a glass of beer, they sink to the bottom before floating up and "dancing" in the glass. 2Scientists investigated this process in a study involving the alcoholic drink beer. It appeared recently in the publication Royal Society Open Science. The scientists say the research helps them understand mineral extraction or bubbling magma in the layer of Earth called the crust. 3Brazilian researcher Luiz Pereira is the study's lead writer. He told the French news agency AFP that he first had the idea when passing through Argentina's capital Buenos Aires to learn Spanish. 4It was a "bartender thing" in the city to take a few peanuts and drop them into beers, Pereira said. 5Because the peanuts are more dense than the beer, they first sink to the bottom of the glass. Then each peanut becomes what is called a "nucleation site." Hundreds of tiny bubbles of carbon dioxide form on their surface. The bubbles act as flotation devices that carry the peanuts upward. 6"The bubbles prefer to form on the peanuts rather than on the glass...," said Pereira, a researcher at Germany's Ludwig Maximilian University of Munich. 7When the bubbles reach the surface, they burst. 8The peanuts sink again before newly formed bubbles send the peanuts up again. Like a dance movement, the peanuts continue sinking and floating until the carbon dioxide runs out, or someone drinks the beer. 9"Beer-gas-peanut system" 10In the experiments, the team of researchers in Germany, Britain and France examined how peanuts acted in what they called the "beer-gas-peanut system." 11They found the larger the "contact angle" between the curve of an individual bubble and the surface of the peanut, the more likely it would grow. 12But it cannot grow too much - less than 1.3 millimeters across is best, the study said. 13Pereira said he hoped that "by deeply researching this simple system, which everyone can grasp, we can understand a system" that would be useful for industry or explaining natural processes. 14For example, he said the flotation process was similar to the one used to separate iron from ore. 15Air is injected into a mixture in which a mineral, such as iron, "will rise because bubbles attach themselves more easily to it, while other (minerals) sink to the bottom," he said. 16The same process could also explain why volcano scientists find that the mineral magnetite rises to higher layers in Earth's crust than would be expected. 17Like peanuts, magnetite is more dense and should sit at the bottom. But the researchers suggest, a high contact angle causes gas bubbles that carry the mineral up through the magma. 18Science is never settled, especially when beer is involved. 19So, Pereira said the scientists hope to create a better model of the dancing peanut action by continuing to experiment with "different peanuts and different beers." 20I'm Dorothy Gundy. 21Pierre Celerier wrote this story for Agence France-Presse. Hai Do adapted the story for Learning English. 22____________________________________________________________________ 23Words in This Story 24bubble - v. to form small ball of air or gas inside a liquid 25magma - n. hot liquid rock below the surface of the earth 26bartender - n. the person who serves drinks at eating and drinking places 27prefer - v. like better than someone or something else 28curve - n. smooth, round line 29grasp - n. an understanding of something