Directed this animation for TED Ed.

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.