People are going to buy cheap fertilizer so they can grow enough crops to feed themselves, which will be increasingly difficult with climate change.

What's amazing is, if young people understood how doing well in school makes the rest of their life so much interesting, they would be more motivated. It's so far away in time that they can't appreciate what it means for their whole life.

With the states release today of a set of clear and consistent academic standards, our nation is one step closer to supporting effective teaching in every classroom, charting a path to college and careers for all students, and developing the tools to help all children stay motivated and engaged in their own education. The more states that adopt these college and career based standards, the closer we will be to sharing innovation across state borders and becoming more competitive as a country.

The only role other than paying their taxes, whatever those are, the only role for philanthropy broadly - of which the rich should give disproportionately - the more, the better - and I think there is a positive trend in that direction - there are certain risk-taking things, like trying out a new type of charter school or funding a new kind of medicine.

We're changing the world with technology.

I've always been amazed by Da Vinci, because he worked out science on his own. He would work by drawing things and writing down his ideas. Of course, he designed all sorts of flying machines way before you could actually build something like that.

Your most unhappy customers are your greatest source of learning.