Growing a coconut?

when i was in elementary school(4th grade) we grew a coconut throughout the whole school year. our teacher didnt plant it in any soil or anything of that nature. instead, she just placed it in a clear square gl dish with water. the coconut was submerged in water half way up. out of the pointy side, over time, it auctually started to grow a branch like thing. eventually even two really big leaves started to come out. at the end of the year i won the raffel and got to take the growing coconut home(which my friends and i broke on the street curb as soon as the bell rang). my question is, was that some sort of special coconut? or was it one that i could just buy at a grocery store and do ths? sorry if this sounds stupid. but im just not sure. to me i think i need to get a sp;ecial coconut from some place. it seems like an egg... you cant hatch an egg thats bought from stop and shop.. but can you grow a coconut that you bought there?