Purpose:Show partial reflections and dependence of wave speed on density of the medium.
Description:A string (running inside the SLINKY) connects one end of a SLINKY with a point about 3/4 of the way from that end, with the end taped to one end of the lecture table. When the SLINKY is extended it has regions with two different densities, causing two different wave speeds. A wave started at the free end of the SLINKY (right side in photographs above) will experience an impedance change; it may produce (quickly attenuated) partial reflections at the boundary. The wave moves more slowly in the section at the left, as seen in the photograph at the right.