Physics behind making fire: The ancient way

Hello. I'm new here and I've started a college level physics course at my college without having any sort of physics background. Nevertheless, I find it quite challenging and fun. I like to understand things from class by applying it to real life. I like to go camping and sometimes I make my camp fires the old old school way, by using a stick and a bow.

http://www.youtube.com/watch?v=NWszLA49swY&feature=related

Something like that ^

Now I'm trying to understand it better. The person creates friction (kinetic energy, right?) by rubbing the stick against wood. The kinetic energy transfers to heat energy after a while, and when the temperature is high enough, it begins to burn the wood.

This is my basic understanding of it. Would anyone care to explain it in a more "physics" "mathematical" way?

Thanks