I roll with it, give 'em short, punchy and factual answers. If you bumble and act uncertain, they get that and keep drilling.
Another tack is to get technical with 'em. Bores them right out.
“Why is the sky blue?”
“Because sunlight is actually ALL colors, but because blue light is more energetic, higher frequency, shorter wavelengths, right?, it bounces around more than other colors.” LOL, and keep going.
Baffle them with technicalities (but don’t make shit up, keep it real!) and they’ll wander off to think about it.