What do I do with the giant spinning pot?

Solution 1:

Yes, you should keep trying! I had a tough time getting a bomb in the first time I played as well. Spoilers from strategywiki.org:

After opening Darunia's house, light the four torches around the pot at the bottom of Goron City. From the second level, throw a Bomb Flower into the top of the spinning pot to stop it. It will stop showing one of three faces, depending on what time you threw the bomb flower in. Alternatively you can wait until after you get bombs from dodongo's cavern and use them instead. If the pot stops on 'happy', a Heart Piece will fly out.

http://strategywiki.org/wiki/The_Legend_of_Zelda:_Ocarina_of_Time/Heart_Containers