Abstract
The water drops falling in a stagnant air were investigated with a stroboscopic camera, and the following results were obtained.
(1) The water drops with their fall velocities larger than 8m/sec were frequently observed.
(2) The surface tension of a dilute solution of silver chloride of 0.01 percent, which was used to make the shape of water drops clear, was found to be the same as that of pure water within the scope of experimental error.
(3) The shapes of falling drops of various sizes were photographed, and it was found that these drops vibrated vertically, even after they had fallen down the distance of 12 meters, and the grade of the drcp deformation was dicussed.
(4) It was sometimes observed that on the surface of a water drop a horizontal stripe or rumple appeared. This is considered to be a shock wave on the drop surface, and to be related to the separation phenomena.
