04:59 Design, Engineering & Technology Why are airplanes slower than they used to be? lesson duration 04:59
05:22 Science & Technology These salamanders snack on each other (but don't die) lesson duration 05:22
05:02 Science & Technology How much electricity does it take to power the world? lesson duration 05:02
05:10 Business & Economics Why good ideas get trapped in the valley of death— and how to rescue them lesson duration 05:10
