This is a well-written article in the Washington Post that shows how a CCD detector that is in digital camera came out of the our understanding of quantum mechanics. The inventor of the CCD won the Nobel Prize for Physics this year.
Getting a digital camera for Christmas? Before you fire it up to capture Uncle Wally's fateful fifth trip to the punch bowl, take a moment to picture this: You've got a genuine scientific marvel in your mitts. In fact, it took nothing less than two Nobel prizes and a revolution in physics in order for you to point and shoot.
Why? Because to take a filmless picture, your camera or camcorder relies on, um, quantum mechanics. In particular, it exploits the fact -- revealed by Albert Einstein himself -- that a beam of light, which behaves like a wave in some circumstances, acts like a bunch of separate particles in other circumstances.
A good article to give to someone who asks you if physics is of any use.