The whole school will hear and want to know the source of such an ear-piercing sound. Contains rods and tubes of varying lengths and thicknesses and resonance powder.  Rod lengths are as follows:

70cm length, 1cm dia, solid

70cm, 1cm dia, hollow                      

70cm, 1.2cm dia, solid

76cm, 1.2cm dia, solid

100cm, 1.2cm dia, solid