Abstract
The shape and fall velocity of raindrops were observed by means of the photographs taken with a dark-field by electric sparks at 100 times/sec. 62 successful photographs of raindrops were obtained. Various waterdrops of known mass were taken in photograph after llm fall in the state of still air, and the relation among the mass, fall velocity and deformation were observed. Raindrops and waterdrops were compared with each other in shape and fall velocity. In the state of still air, the shapes and fall velocities of raindrops and waterdrops were similar. The maximum fall velocity was 980cm/sec, and the largest diameter was 0.51cm. The drag coefficient of raindrop is discussed on the basis of these data.
