Does it take more energy to skip or run to the pizza restaurant?
Our readers tell questioner Jessica, age 5, that it is definitely more efficient to run to the restaurant - and encourage her to keep up the exercise!
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This week鈥檚 new questions
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Why do some flowers close up at night but others stay open?
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How do you check the accuracy of an atomic clock?
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This week鈥檚 new questions
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Did abstract mathematics exist before the big bang?
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This week鈥檚 new questions
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How did marine reptiles such as ichthyosaurs breathe?
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Could aliens work out if a human or an ape built the tomb they lie in?
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This week鈥檚 new questions
Why do large military planes generally have wings at the top of the fuselage, but on large commercial planes the wings are at the bottom? And what would happen if time stopped?
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Why do ice cubes for my gin and tonic often shatter in the mould?
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Once life is established, is intelligence inevitable? Part 2
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This week鈥檚 new questions
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Why didn鈥檛 green fur evolve among mammals?
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