Science

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Move over solar and wind power, there’s another renewable energy source: poop. Thanks to rapidly advancing “digester” technologies, it’s possible to extract and refine natural gas from the methane in human and animal waste, generating power rather than polluting greenhouse…

Mar 26

Why do we tip?

Some people tip to show off. Some people tip to help the server. Others tip out of a sense of duty. Michael Lynn of Cornell University's School of Hotel Administration weighs in on the psychology behind tipping in America.