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How a 'Toaster' Could Help Solve Our Energy Problems

A TED-Ed lesson that starts with the 1919 automatic toaster and ends with a giant modern one — a machine that heats bricks, rocks, and molten salt to store energy for industry, using the same heat-from-electricity trick.

How it works

  • Press play to start the video.
  • Videos 5 minutes or longer pause once or twice for a quick check. Get it right and you're on your way. If not, you'll see a friendly explanation and the video simply keeps going. Short videos skip the checks.
  • At the end there's a 3-question test. Score 60% or more to complete the lesson, and 80% or more to master it. You can always watch again and try for a higher score.

Practice it on paper