i don't have any kids of my own, but have had plenty of opportunities to babysit. what i always do if kids ask a question i don't know is tell them i don't know, but lets go look it up. Then i go on my phone or on a computer to wikipedia and look it up with the kids right there. Even if the kids aren't able to read yet, there are pictures and you can explain it to them as you learn it yourself. I'm hoping i might spark their curiosity this way, and also once they're a little older the desire to go and research something that they don't know but are curious about.