Pratique du Shadowing: What if you dropped a bowling ball in the Mariana Trench? - Apprendre l'anglais à l'oral avec la vidéo
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This question comes from Doug who asks, If you were in a boat directly over the Mariana Trench and dropped a 7kg bowling ball over the side, how long would it take to hit bottom?
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It's a good thing you mentioned the mass because of a very surprising fact.
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Most bowling balls float.
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Bowling balls all have about the same volume, so they all displace the same amount of seawater, 12.13 pounds, or about 5.5kg.
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But the weights of the balls themselves vary substantially, from as little as 6 pounds to a maximum of 16.
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Only the balls that weigh more than 12.13 pounds will sink.
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Hang on a moment, the serious bowlers are saying.
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Most bowling balls are at the heavy end of that range.
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The average ball surely sinks.
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This is definitely true for serious bowlers, but for the overall population, it might be better to define the average ball using the
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distribution of ball weights you might find at the rack at the local bowling alley.
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So I sifted through a bunch of online photos taken at bowling alleys and tallied up the weights visible on the balls.
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The average was 10.5 pounds.
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For most people, the average bowling ball they've picked up on their lives probably floats.
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If nothing else, this makes the popular simile, Sank like a bowling ball, seem a little poorly chosen.
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But Doug's bowling ball is 7 kilograms, or 15 and a half pounds, making it plenty heavy enough to sink in the ocean.
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How fast will it fall?
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The speed of a bowling ball falling through water is driven by both the drag equation and the ball's apparent weight.
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For Doug's bowling ball, the terminal velocity will be roughly 1.3 meters per second.
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The Mariana Trench is 11 kilometers deep, so the ball will take about 2 hours and 20 minutes to reach the bottom.
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A 13-pound bowling ball, which is much closer to neutrally buoyant in seawater, would take over 4.5 hours to reach the bottom.
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On the other hand, a bowling ball made of solid iron would reach the bottom in half an hour.
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A bowling ball made of lead would reach the bottom in 24 minutes, and one made of solid gold would make it in 18.
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However, a bowling ball made of solid gold would weigh more than the average bowler.
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It would also be worth over 10 million dollars, so I'm not sure why you're throwing it in the Mariana Trench.
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A bowling ball made of solid osmium, the heaviest naturally occurring element, would weigh over 250 pounds and could sink to the bottom of the Mariana Trench in just 16 minutes.
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But what if the bowling ball you were using was the average 10.5-pound bowling ball?
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Then, the ball would never reach the bottom.
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Instead, it would float sideways along with the currents.
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We can track what course it would take using the Plastic Adrift Ocean Plastic Tracking Tool.
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The bowling ball would first drift west, past the Philippines, then probably north along the coast of China, turning right at Japan and heading out across the Pacific.
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Three and a half years later, it would approach California.
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Most likely, it would follow the coast for a little while and then become swept up in the Great Pacific Garbage Patch.
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However, it's possible that it would be swept up on shore instead.
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If, during those three years, Doug took his boat from the Mariana Islands to Los Angeles, found a nice sheltered cove, and set up ten carefully weighted bowling pins just below the surface,
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then there is a tiny, tiny, tiny chance that he could succeed in bowling the single most improbable strike of all time.
À propos de cette leçon
Vous vous entraînez en anglais avec "What if you dropped a bowling ball in the Mariana Trench?" en utilisant la technique du Shadowing.
Qu'est-ce que la technique du Shadowing ?
Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.