View full lesson: http://ed.ted.com/lessons/why-wildfires-are-necessary-jim-schulz Our early ancestors relied on lightning to cause forest fires, from which they could collect coals and burning sticks to help them cook food and clear land. Yet,... Read more »
View full lesson: http://ed.ted.com/lessons/what-is-entropy-jeff-phillips There’s a concept that’s crucial to chemistry and physics. It helps explain why physical processes go one way and not the other: why ice melts, why cream spreads... Read more »