Google Science Fair 2012
google.com
google.com
"Why do cats purr?" Evolved basic social actions, display of affection/assuagement.
"Is it better to boil or bake?" Boil water, bake cake (or get bake).
"Can robots change their mind?" Only if they were programmed with algorithms that enabled them to.
"Why do some things bounce?" Newtonian laws of conservation of momentum, angular momentum and energy.
"Why do spinning balls curve?" The spin of the ball forces air around it in the direction of spin, coupled with a forward motion this produces a difference in air pressures on either side of the ball causing it to 'curve' a path through the air.
I can't help but feel the kids time would be better spent aiming their question at wikipedia instead of another thinly disguised Google Co. marketing site! ;)
Yes, you can search Wikipedia for answers to any of the answers to the questions you list. That's not the point. If you do that, you'll be completely lost when you need an answer for a question than nobody, anywhere, has ever investigated before.
I wish this point was drilled into kid's head in elementary school. It's not what you know, it's what you do when you find something you don't know.
(Aside from that, all of the questions you list have much deeper answers than the ones you give. "Can robots change their mind? Only if they were programmed with algorithms that enabled them to" is false in the era of machine learning, or tautological if you count machine learning as "an algorithm that enabled them to." "Why do some things bounce? Newtonian laws of conservation of momentum, angular momentum, and energy" ignores the vast field of material science, and questions like why does rubber bounce while clay does not, and why does silicone not bounce very much yet if you add boric acid to it (making Silly Putty [tm]), it bounces a lot?)