The flotation process . Fig. 24. These phenomena indicate that the particles at the surface of aliquid have a greater coherence than the particles in the interiorof the liquid. The force that does this is surface tension. Theexperiment with the ring and the loop, for example, is explainedby the fact that, in the first place, the surface tension of theliquid acts equally on both sides of the cotton, but when the filminside the loop is broken, the surface tension only acts on one side,and hence draws the loop out into a circle, f Surface tension can be measured. A framework^ (Fig- 25) consist- A
The flotation process . Fig. 24. These phenomena indicate that the particles at the surface of aliquid have a greater coherence than the particles in the interiorof the liquid. The force that does this is surface tension. Theexperiment with the ring and the loop, for example, is explainedby the fact that, in the first place, the surface tension of theliquid acts equally on both sides of the cotton, but when the filminside the loop is broken, the surface tension only acts on one side,and hence draws the loop out into a circle, f Surface tension can be measured. A framework^ (Fig- 25) consist- A C E B. Fig. 25. arrangement for measuring strength of film. tA Text-Book of Physics, by W. Watson, page 191. IA Text Book of the Principles of Physics, by Alfred Danniell, 1911. 128 THE FLOTATION PROCESS ing of a transverse bar A B, and two grooved slips C D and E F,will allow the piece of wire G H I J to slip freelj^ up and down. Thewire H I is pushed against A B and a quantity of the liquid isapplied between them. The little pan X is loaded wdth sand untilthe wire H I is pulled from A B. The minimum force required todo this is 77ig, the weight of m grams. This weight suspended on thefilm equals the tension of the film on the wire. If the film stretchesuntil the wire S^ / is at p, then the film has an area C Thetotal weight mg is distributed over the breadth C E; whence, if Trepresents the superficial tension across the unit of length C E, then mg = E or T = ^ Thus the force of surface tension between water and air has beendetermined; it is 3^ grams per linear inch or 81 dynes* pe
Size: 2025px × 1234px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidflotationpro, bookyear1916
