From Harvard Magazine:
The nanoscale world is the realm of the truly small. One nanometer is a billionth of a meter, about 100,000 times thinner than the sheet of paper on which these words are printed. If you could shrink to that height, atoms would be from ankle- to waist-high, and a single molecule would wiggle and jump as you watched an electron pass through. The ridges of an old 33-rpm vinyl recording would rise before you like mountain ranges (pictured on this page, several tracks from the Beatles’ “Eleanor Rigby”). You would quickly realize that objects and forces from your new vantage point are not just quantitatively smaller, but qualitatively different. Matter at that scale sometimes defies classical, Newtonian physics. Light is seen to be both a wave and a particle. Caged electrons tunnel through atoms-thin walls, releasing energy as they escape confinement. Proportionally, surface area becomes vastly larger and more important than volume, leading to significant changes in physical properties.