Artist: Don MacLane
Stainless steel, basalt, on granite base, 2015
Dimensions at rest: H 29" x W 18.8" x D 4" (rocker diameter)
Dimension in motion: H 29" x W <58" (mast tip at full travel)
Granite Slab: 10.4" x 39" x 1.2" (42 lbs)
A cylindrical rocker supports a pendulum with a fixed stone weight and stainless counterweight. The mast on the rocker has a movable counterweight. As the rocker and pendulum move, energy of these elements cycles between kinetic and potential forms and is transferred between the elements. Since the periods of motion of the rocker and pendulum are not equal, there is an interesting pattern of motion as one catches up to then passes the other. The movable counterweight can be positioned to alter the period or frequency of the rocker and thus change the pattern of motion of the sculpture. The rod that the weight slides on is marked. Positioning the weight so its upper surface aligns with these marks result in approximate frequency ratios: 2:1, 3:2, 4:3, 5:4, 1:1 (fp:fr, from the top of the rod down). Experimenting with weight placement at or near these marks will yield interesting motion patterns.