Understanding Processes on the Microscale

Many physical processes do not scale uniformly in the microscale domain i.e.  

At the millimetre scale, gravity, friction, combustion and electrostatic forces predominate. At the micrometer scale, it is mainly electrostatic forces, van der Waals forces and Brownian motion that are at work. Forces related to volume, like weight and inertia, tend to decrease in significance while forces related to surface area, such as friction and electrostatics, tend to increase in significance. Surface tension, which depends upon an edge, and viscosity both become very significant and impact hugely on the movement of liquids as discussed in the previous section. Hence, sometimes these processes can aid the development of chip-based devices while in other cases they present limitations. 

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