When a drop of liquid splits into a number of drops, each drop tries to minimize its area but the overall surface area of drops increases. How does the overall surface area of the drops increase????
2 Answers
It does not try to minimize it's total surface area,rather it minimizes it's $\frac{surface \\\ area}{volume} $ ratio to attain minimum potential and thus the droplets assume spherical shapes as it is the best way to do so.
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How does the overall surface area of the drops increase????
It’s just geometry.
The area of a sphere with radius $r$ is $A=4\pi r^2$ and the volume is $V=\frac43\pi r^3$, so the relationship between area and volume for one sphere is
$$A_1=4\pi\left(\frac{3V_1}{4\pi}\right)^{2/3}=CV_1^{2/3}$$
where $C$ is a numerical constant.
Now suppose one sphere of volume $V_1$ divides into $N$ spheres each of volume $V_1/N$. Their total area will be
$$A_N=NC\left(\frac{V_1}{N}\right)^{2/3}$$
or
$$A_N=N^{1/3}A_1.$$
Thus the area increases as the cube root of the number of spheres.
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