Evening Republican, Volume 21, Number 46, Rensselaer, Jasper County, 4 March 1918 — FILM SPREAD OVER WATER [ARTICLE]

FILM SPREAD OVER WATER

Thin Sheet on Surface Has Properties That Are Very Like Those of India Rubber.

It seems not to be generally understood that the surface of all water Is Covered by a film of the water Itself, which in its action is not unlike that of a thin sheet of India rubber, says Edward Bigelow, naturalist, in Boys’, Life. To comprehend this one must imagine the rubber to be so thin as to be transparent. The surface of the water itself is elastic and under tension, so that a needle, though heavier than the water, may be floated on the surface. Several Interesting experiments may be made with the elasticity of this film. One of the best is to place two slender splinters of wood side by side on the water. Now drop a little alcohol between the splinters. This alcohol will immediately break the surface film between the splinters, and the pulling force of the remaining film, since there is nothing between them to hold them, will cause the splinters instantly to fly apart. Another interesting experiment is to whittle a thin, Biq£der splinter, pointed at one end somewhat like a boat. Place a tiny bit of gum camphor on the rear of this splinter and the gum will destroy the surface film so that there* will bd no pull in the rear. As there is a pull in the front not balanced by one in the rear, the tiny boat will run forward as rapidly as the camphor can dissolve the film in the rear. Some interesting little “magic” tricks might be developed from these experiments which would surprise and instruct your friends.