11 orbs were made with various numbers of strands of metal tinsel. The relative weight of each
orb was calculated based on the length of the strands in each orb and the number of strands. 3
PVC pipes were cut, each being 60cm long. The diameters of the pipes were 20, 42 and 60mm.
Initially, my hair, a cushion from the sofa, a woollen sweater and a piece of carpet were used as
the rubbing materials. At the start, the cushion, hair and wool appeared to behave in a very
similar way so the cushion and hair were not used in the main experiments