The physics of sperm vs. the physics of sperm whales - Aatish Bhatia

source: TED-Ed 2013-09-23
View full lesson: http://ed.ted.com/lessons/human-sperm...
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.
Lesson by Aatish Bhatia, animation by Brad Purnell.

The most groundbreaking scientist you've never heard of (by Addison Anderson)

source: TED-Ed 2013-10-01
View full lesson: http://ed.ted.com/lessons/the-most-gr...
Seventeenth-century Danish geologist Nicolas Steno earned his chops at a young age, studying cadavers and drawing anatomic connections between species. Steno made outsized contributions to the field of geology, influencing Charles Lyell, James Hutton and Charles Darwin. Addison Anderson recounts Steno's little-known legacy and lauds his insistence on empiricism over blind theory.
Lesson by Addison Anderson, animation by Anton Bogaty.