The Gravity Bong I was introduced to the gravity bong by a friend. He told me the full name as described to him was the "Afghanistan Gravity Bong". We were sitting around one night and decided to try one out. While I could go into detail concerning the mechanics of the bong's operation, I don't think that is really necessary. The reason it is called a "gravity bong" and not something else is this is what someone called it, that is how they described it to their friends, and now it is an accepted term for the following setup. I have observed some people on the net arguing about gravity vs. pressure vs. w