Comment Just be clear and use plain English (Score 1) 430
Obviously 2nd graders are not going to understand technical terms they're not familiar with (or are familiar with but misunderstand their meaning), but I'm shocked to see how many people commenting on this question underestimate the intelligence of 2nd graders. When I was a child I had been using computers since before I was in kindergarten; back then there were still many people back then who didn't have computers at home. If they hadn't encountered computers at home, they were certainly exposed to them in school. Nowadays, computers are ubiquitous in homes, and that's not counting other electronics that generations of Americans have grown up with. Kids are familiar with computers because they're a fact of life.
Personally I'd love to talk to kids about computers, because they'll be eager to learn and will have lots of questions because they are aware of the fact that computers are present in their lives and that they have gaps in their understanding. You just have to give them simple and clear explanations so that they can establish their general knowledge more, and don't delve into really specific technical issues or nuanced examples (I know we love to do that, but restrain yourself). Tell them a little bit about what computers do, why they're important, what programming has to do with computers, and why programming is important. I'm sure they'll eat it up as long as you don't bore them with overly lengthy explanations. It's just like talking to any adult who is not familiar with computers, except the children will comprehend more and learn faster than a computer-illiterate adult would (don't be surprised when the kids get what you're saying but their teacher doesn't). Kids are biologically equipped with learning super powers--use that to your advantage.