Earworms: Those songs that get stuck in your head - Elizabeth Hellmuth M...

source: TED-Ed     2015年3月26日
View full lesson: http://ed.ted.com/lessons/earworms-th...
Have you ever been waiting in line at the grocery store, innocently perusing the magazine rack, when a song pops into your head? Not the whole song, but a fragment of it that plays and replays until you find yourself unloading the vegetables in time to the beat? Elizabeth Hellmuth Margulis explores earworms — a cognitive phenomenon that plagues over 90% of people at least once a week.
Lesson by Elizabeth Margulis, animation by Artrake Studio.

What did democracy really mean in Athens? - Melissa Schwartzberg

source: TED-Ed      2015年3月24日
View full lesson: http://ed.ted.com/lessons/what-did-de...
While we might consider elections to be the cornerstone of democracy, the Athenians who coined the term actually employed a lottery system to choose most of their politicians. Melissa Schwartzberg describes the ins and outs of the Athenian democracy, and addresses some ways in which a lottery system might benefit us today.
Lesson by Melissa Schwartzberg, animation by TED-Ed.

Where did Earth’s water come from? - Zachary Metz

source: TED-Ed      2015年3月23日
View full lesson: http://ed.ted.com/lessons/where-did-e...
Water covers over 70% of the Earth, cycling from the oceans and rivers to the clouds and back again. It even makes up about 60% of our bodies. But in the rest of the solar system, liquid water is almost impossible to find. So how did our planet end up with so much of this substance? And where did it come from? Zachary Metz outlines the ancient origins of water on Earth.
Lesson by Zachary Metz, animation by The Moving Company Animation Studio.