Inside Dielectrics: Feynman's Physics Explained

Feynman Vol II10-11

A material can polarize in two ways. In nonpolar molecules a field distorts the electron cloud to induce a dipole; in polar molecules like water, which already have a permanent dipole, the field tries to line them up against the scrambling of thermal motion. In a dense material the field on any one atom is not just the average field but is modified by its polarized neighbors — a 'local field' effect captured by the Clausius-Mossotti relation.

The big idea

Inside dense matter, every atom feels its neighbors' fields too.

Think about it

Why does heating a material make it harder to keep its molecular dipoles aligned in a field?

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