Abstract
The downdraft produced by falling waterdrops was measured, using a vertical U-shaped tube.
The results showed the magnitude of the downdraft to be much less than expected, even though the measurements included the downdraft produced by the dragforce of the falling drops and that resulting from their negative buoyancy. It was also found that the magnitude of the two components was approximately equal.
With regard to the negative buoyancy resulting from the weight of raindrops, it was proposed that, in a parcel of air which contains falling raindrops, air resistance is exerted on each drop individually rather than on the parcel of air as a whole. If this should be the case, it would easily explain why the magnitude of the downdraft produced by individual raindrops is so much less than expected.
