You can't interest all kids in an impromptu science lesson. In fact, most of them are loathe to participate in the science lesson at school that the government obligates them to attend. So don't be too harsh on kids who run the other way when you follow them outside carrying a periodic table. Instead, trick them.
That's right. You can turn to good old-fashioned deception to get the kids to use science without them even knowing. The trick is to oh-so-casually ask a few questions or prompt a conversation during the course of your average snowman building practice. (We're just taking it for granted that they will want to build a snowman, since that's generally regarded as the most fun you can have in the snow.)
Don't attempt any hard-hitting questions, or they'll sniff you out. (Any parent who casually says something like, "I'm just curious, what's the atomic mass of the hydrogen or oxygen that make up this snow" isn't getting anywhere.) Instead, test the theory of Frosty by asking them to find ways to make their snowman or lady stick around longer. Would making it bigger help? Or trying to incorporate ice? Where should you build it so it doesn't melt as fast? Before you know it, the kids will be using science gleefully.