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/how-do-tornadoes-form-james-spann Tornadoes are the most violent storms on Earth, with wind velocities that can exceed 200 miles per hour. How do these terrifying cyclones form? Meteorologist James Spann sheds... Read more »
View full lesson: http://ed.ted.com/lessons/how-tsunamis-work-alex-gendler The immense swell of a tsunami can grow up to 100 feet, hitting speeds over 500 mph — a treacherous combination for anyone or anything in its path.... Read more »