Puddle Distortions

The size of the drop is such that its surface area remains equal to its initial value, which fixes the radius R. The puddle is the seat of a certain internal pressure P2 0. 

These types of experiments can all be conducted in an unglamorous kitchen, with nothing more than a puddle of oil sitting on the surface of water and a few bobby pins to pull on the edges. 

FIGURE 3.10. A puddle of oil deposited on water and stretched by either 2 pins (a) or 4 pins (b). 

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