The Answer:

The first step toward today's bar codes and bar code readers came in 1948. Graduate student Bernard Silver mentioned a conversation he'd overheard about capturing product information automatically at checkout to his friend Norman Joseph Woodland, a 27-year-old graduate student and teacher at Philadelphia's Drexel Institute of Technology.

Silver and Woodland's experiments resulted in a very raw bar code reader in 1951. It was about the size of a desk and used light and pieces of reflective paper. The two were granted a patent for the bar code reader in 1952. Early forms of the bar code and reader were tested by railroad companies who used them to track freight cars and by distributors who used them to track shipments.

The availability of cheap lasers in the 1960s and the standardization of the Universal Bar Code in 1973 were important events in the history of the bar code we know today.

And finally—to answer your question—on June 26, 1974, all the tests were done and at a Marsh super-market in Troy, Ohio, a single pack of chewing gum became the first retail product sold with the help of a scanner.

Here are links to three informative articles about the history of the bar code:

• Bar Codes are Sweeping the Nation
• Bar Code 1
• Barcodes

And don't forget to browse the Inventions and Discoveries channel at infoplease.com.

—The Editors