Unformatted text preview: F that acts just as the adhesion of the liquid lets go of the slide. This force is then related to the surface tension σ by σ L F 2 = , (1) where L (in m) is the length of the slide. The factor of 2 arises from the fact that there is a boundary on either side of the slide. To measure the force F we use a torsion balance (see figure) that sits on a movable lab jack that allows us to move the balance up and down. With the weight pan empty, we make contact between the slide and the liquid surface. We then raise the balance slowly, carefully observing the position of the pointer K on the scale S. Determine the position at which the contact with the liquid breaks. Then, with the slide out of the liquid, add weights to the pan until the same position of the pointer is achieved. From the weights necessary we can then determine the force F . Figure 1: Torsion balance 91 - 1...
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This note was uploaded on 01/20/2012 for the course P 309 taught by Professor Urheim during the Spring '11 term at Indiana.
- Spring '11