Your five-year-old's at that stage-you know the stage-where he's discovered his own brain. And he realizes that the world around him is full of stuff he doesn't understand. But, like the genius you hoped he'd be, he sees no reason why he shouldn't know everything there is to know-today. And naturally, he expects you, since you're older, presumably wiser, and the donor of half his DNA, to explain everything to him. Today.

You faked your way through the explanation of why leaves change in the fall, you managed something reasonably logical, but probably wrong, about why the wind blows, and you totally made up something about how cars run, before changing the subject, really fast.

But now it's winter, and today, it's snowing. You tried keeping the blinds closed, you tried to interest him in playing a video game, you even tried to capture his attention with candy-but you failed.

He stares out that window at the big, fat flakes, falling from the sky, and you know he's trying to work it out (he watched the snow last year, but that was before he discovered his brain). You can feel that young mind working, you know it's coming, and your Diversion Bag-Of-Tricks is empty. He turns to you-"Please ask for a new puppy", you think, trying to zap him, telepathically-but no, he asks The Question: "Mom, what is snow?"

OK-control your breathing, and calmly force yourself to smile. You can get through this, with a fairly simple explanation, which should satisfy him, at least until high school Science class:

Remind him that you told him that clouds are made of water vapor-that fog-like stuff that shoots out of your mouth and nose, when you breathe, outside, on a cold day. In the winter-time, when it's really cold out, the water vapor in the clouds gets super cold and really thick and heavy and falls from the clouds in the form of little ice crystals (like tiny, tiny ice cubes), which we call snowflakes, instead of raindrops. He knows by now (he's a genius, remember) that ice cubes can be piled up on each other until they melt, turning back to water; it's the same with the snowflakes.

Granted, there's more to it-snowflakes aren't simply frozen raindrops (that would be sleet), and most snowflakes are made up of more than one ice crystal, based on the denseness of the vapor in the cloud, how fast the vapor is supercooled and blah blah blah. But quick-before your son's budding Einstein-like intellect has the time to expose the gaps in your scientific knowledge, hit him with God's-Gift-To-Mothers-Who-Want-To-Sound-Brilliant:

"And you know what? Every snowflake is different. No two are exactly alike!"

He won't believe you, so prove it to him. Bundle him up, grab a dark piece of paper and take him out into the snow. When the paper has cooled to the outside temperature, hold it flat and catch some snowflakes. Tell him to look real close and he'll see that they're all different.

Trust me-this new discovery alone will keep him occupied and question-free, at least about snow, for the rest of the winter.

Now who's the genius?