My Rock'n Rattles actually started a year and a half ago. They are made from gourds my grandma grew in her garden. After the gourds were dry I picked them from the garden. Next my grandpa drilled holes in them for me. Then I decorated them with paint my grandma had. Next I filled one gourd with BBs and the other with peas and I taped the holes shut.
To change the sound you put different materials in the rattles. To get a loud dynamics you shake it hard and to get a soft sound you shake it easy. The timre of the sound is gravely.