Sprite: [sigh] Mom, why does my room get messy so quickly?
Me: It’s entropy, sweetie.
Me: Entropy. [Handing Sprite our new Kingfisher Science Encyclopedia] Look it up.
Sprite reads the encyclopedia entry and looks at me with a smile.
Me: So, in your case, what is the system that is moving towards disorder?
Sprite: [with a groan] My room!
So there’s a teachable moment. That one short encounter involved vocabulary, science, and research skills. I knew we needed a science encyclopedia. We’ve had it only few days, and it’s come in handy several times already. I got it used at Better World Books, a good but slow option for getting books overseas. [By the way, there's a newer version than the one we bought, but I linked to the actual edition that we have.]