Some qualitative and quantitative aspects of the fast-rotating clinostat as a research tool.

In 1958 the geneticist H.J. Muller proposed an extension of the principle of the (slow) plant clinostat which --to a certain extent--abolishes g effects on plant growth (geotropism). Muller predicted that a feeling of weightlessness would be experienced by a human being attached to a clinostat platform, the rotation speed of which is enhanced compared to that of the plant clinostat. This method (called fast-rotating or fast clinostat) was developed by the author in the mid 1960s to investigate the effects of weightlessness on small living objects. This chapter describes the method qualitatively on the basis of a macroscopic functional model and of empirical results obtained using a fast-rotating clinostat microscope. Some practical hints in using the slow and fast clinostat principles are given.