One carbon atom

Too much information is not always a good thing. I was at a drugstore trying to decide between two types of rubbing alcohol. Both appeared to be the same, so I called my husband, a chemical engineer. “What’s the difference between isopropyl rubbing alcohol and ethyl rubbing alcohol?” I asked.

“Easy,” he said. “One carbon atom.”

Source: http://science.kukuchew.com/2008/01/07/one-carbon-atom/