Green Means Caution, White Means Go?

Although it is universally understood by drivers of all ages these days, green didn't always mean "go" for traffic lights on the road. The first traffic signals used the color red to mean "stop," green meant "caution," and white meant "go." This system of color changed after an accident occurred: A red lens fell out, so the red light appeared white, which meant "go." The green and red color scheme comes directly from railroad signals.

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Key Facts In This Video

  1. Placing images of waterfalls in restrooms has been shown to help shy bladders go. 00:18

  2. White light initially meant "go" for traffic lights. 00:27

  3. Eating popcorn during movies got popular during the Depression in the U.S. when theater owners added snacks to increase revenue. 01:29

Written by Curiosity Staff July 16, 2015

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