SciShow - Why Are Some World Records So Hard to Break?
Why are some athletes able to crush world records when other records remain unbroken for years? The answer has to do with the kind of materials used in the competition and the type of athletic event one is competing in. Hank Green explains in this episode of SciShow.

This episode is inspired and brought to you by the upcoming Focus Features film, RACE, which releases nationwide on February 19th. Watch the trailer here.