Use 1 x 2 stock hardwood (Actual size is .75 x 1.5) Using 12 segments to make a ring. Make 4 to 7 rings in height. Formula for angle of segments is 360º / 12 segments with 2 angle cuts each (24 angles) = 15º 360 / 24 = 15
(If you were going to make 9 segment rings it would be 360 / 18 = 20º Angle cuts)
12 Segments that are 3" long will produce a bowl 10.25 to 10.75 inches in Diameter. Smaller segments will produce a smaller bowl.
About 11 inches in diameter is about the Maximum capacity of the Lathe in the Woodshop.