QR codes are little black-and-white squares that you might have seen on food packages, movie tickets, restaurant menus, and lots of other places. You take a picture of the code with your smartphone and then your phone takes you to a certain website! But how does your phone know what all those random little dots mean? We asked computer engineer Sam Dickerson to help us find the answer.

Got a question that you just can’t crack? Send it to us at BrainsOn.org/contact, and we’ll help decode the answer.

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