This is an excellent scientific novelty which causes amazement when people see it for the first time, irrespective of whether they are scientifically minded. (The version in the Davenport Collection was made for an American company, hence disk rather than disc.) The base is a slightly concave mirror on which you spin a heavy disk, much like you would spin a coin on its edge. However, unlike a coin, the heavy disk spins for a very long time and, as it slows, the sound it makes changes. There is a real surprise when it stops. There are a number of magnetic pieces with holographic surfaces which can be placed on the flat surface of the disk and which create intriguing light and colour patterns as the disk rotates. According to the box it was invented by Joseph Bendik in the 1980s. Made in Taiwan.