History Of Light

NPR's Planet Money had a recent fun podcast on the "History of Light".

One fascinating tidbit was on how much artificial light you can get for a day's labor:

Antiquity: 10 minutes (candle)
1800s: 5 hours (kerosene)
Today: 20,000 hours (electricity)

If you don't want to listen to the audiofile, here's a transcript of that segment.