Educational film demonstrating the concept of surface tension
A British Instructional Film.
A block of rock is measured. Gasworks. A glass of water is poured from a jug. Surface of water with tiny water bugs running around on top. C/U of a sewing needle held in tweezers. Needle placed on piece of paper floated on top of bowl of water. Paper removed and needle is then floating on the surface. A watch spring is floated. A special float is placed in water. Liquid drops in C/U. Soap solution added to water and spring sinks. Ether vapour placed on surface of water and float rises. A square of cork is shown in C/U. A small piece of camphor is inserted into one edge. When cork placed on water the square rotates. Toy boats move on water. A film of soap solution - a bubble is blown. A wire shape is attached to the bubble and the bubble stretches.
A bubble is subjected to "rough handling" (!) until it bursts. Two bubbles are banged against each other. Films of soap solution are produced on different wire frames. A bubble is punctured through a hole in a paper washer and changes shape as the air leaves the bubble. Capillary attraction. Experiment showing how liquid rises against the force of gravity. Diagram representing glass tubes of different sizes to show effect of gravity on surface tension. Blotting paper absorbing ink. Blotting paper under microscope. Lamp wick drawing liquid up from a glass. Burning of a wick. C/U of flame of candle. Paintbrush being placed in and taken out of a glass of water showing change in shape. Destruction of mosquitoes. Larvae hang below the surface of the water. A man sprays oil on the water and this reduces surface tension. The larvae then die as they cannot hang on to the surface and therefore cannot breath. Shot of a tropical area made safer for human habitation through this means.
Revised with the Co-operation of the National Committee for Visual Aids in Education.