Effect of long-range intermolecular forces on the drag of an oscillating disk and on the viscosity of gases

An experimental investigation has been made to determine the changes produced by ionization in the apparent viscosity of gases. The method used is that of the oscillating disk. In one series the gas was ionized by the gamma rays from an externally placed cesium-137 source. In the other two series of measurements the ionization was achieved with the aid of the alpha particles emitted from the surface of the oscillating disk coated with polonium 210.The measurements were made on nine gases at room temperature and in the pressure range of 1 mm Hg to 1.7 atm. The gases were: dry air, nitrogen, carbon dioxide, oxygen, helium, neon, argon, krypton and xenon. The experimental results showed that there is a very small change in the skin friction experienced by the disk.