This wooden pendulum has a strong and sturdy construction ideal for classroom use. The blue pendulum bob is adjustable so that students can easily and quantitatively study the relationship between the length of the pendulum and the period of the bob. Wooden guide helps students to keep the release angle uniform and small and the rigid body allows for movement in only two dimensions keeping students focused on the relationship of length and period without having to worry about other variables. Includes an instruction manual to fascilitate student and teacher use of the apparatus. 15 1/2" tall with the wooden pendulum 12 1/2" wooden pendulum with adjustable bob. Base is 3 1/2" x 6 1/2".