Imagine trying to describe an iPhone to someone circa 1965. The first episode of Star Trek aired in 1966, so using the word tricorder is cheating. Remember that you'll be speaking to a generation where computers don't have screens, take up entire rooms, and cost $100,000+.
Fast forward to somewhere a bit before 2007 and you would still have some trouble. In 2006 the best you could do was a fancy camera phone. Today, in 2015, we take it for granted that we have tiny computers in our pockets.