They range in size from a few microns to a few millimeters. This field, which encompasses all aspects of science and technology, involves things on a smaller. Creative people from all technical disciplines have important contributions to make. You are encouraged to join the excitement. Things behave substantially differently in the micro domain.
Forces related to volume, like weight and inertia, tend to decrease in significance.
Forces related to surface area, such as friction and electrostatics, tend to become large. And forces like surface tension that depend upon an edge become enormous. It takes a while to get one's micro intuition sorted out. An ant carrying many times its weight or a water bug walking on the surface of a pond are just two manifestations of this different micro world.