The physics of sperm vs. the physics of sperm whales.

Aatish Bhatia of TED-Ed asks the question, how are the physics of a single sperm and sperm whale different?

It’s all comes down to the Reynolds number. For a huge whale, a single stroke of its tail can propel it extremely far in the water. But for micro-organisms like a sperm, moving through water molecules that are nearly its same size can be extremely difficult.

http://www.youtube.com/watch?v=U9g4gRWkFTs