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The physics of human sperm vs. the physics of the sperm whale

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TEDEd Animation

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Traveling is extremely arduous for microscopic sperm -- think of a human trying to swim in a pool made of...other humans. We can compare the journey of a sperm to that of a sperm whale by calculating the Reynolds number, a prediction of how fluid will behave, often fluctuating due to size of the swimmer. Aatish Bhatia explores the great (albeit tiny) sperm’s journey.

The video creates a distinction between the "low Reynolds number world" inhabited by microbes such as bacteria and sperm, and the "large Reynolds number" inhabited by macroscopic creatures like humans or whales. Based on what your learned in the video, why is it more difficult to swim in a low Reynolds number world compared to a large Reynolds number world?

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Aatish Bhatia
  • Animator Brad Purnell
  • Narrator Addison Anderson

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