"Want to know the best thing about being a professor? Colored chalk." That's the word from MIT engineer Donald Sadoway, whose class is one of the largest in the history of the school and whose online TED chalk talk has logged more than 380,000 views. The talk is on the unsexy topic of liquid-metal batteries, but you'll enjoy it so much you'll feel guilty. That's because Sadoway does more than entertain; he gives you a glimpse into the future of energy.
One problem with renewable energy sources is that they're intermittent. No sun, no wind, no juice. What's needed are grid-level batteries that can store power when it's being produced so it can be used in off-hours. But the batteries have to be huge and cheap, and Sadoway, 62, is figuring out how to make them using molten salt and liquid metal. The batteries work, and he and his team are now scaling them up for grid-level use. In case you need one more reason to find Sadoway cool, consider that he is the only expert on that team. The others are students. "In a battery, I strive to maximize electrical potential," he says. "When mentoring, I strive to maximize human potential."
Kluger is TIME's science editor
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