為什麼金屬的外表會這麼閃亮？

Light waves are electromagentic waves in nature. It consists of time varying electric anf magnetic fields.

When light waves strike the surface of an object, because of the action of the eelctric field components of the light (electromagnetic) waves, the electrons of atoms in the object begin vibrating. If the frequency of the light wave do not match with the natural frequency of vibration of the electrons, these electrons only vibrate with brief periods of time with small amplitudes, then the energy is reemitted as light wave. If the material object is opaque, the electrons of atoms at the material's surface vibrate at short periods of time and then reemit the energy as reflected light waves.

Metals usually contain abundance of free electrons. These free electrons are more prone to vibrate by the electric field components of the incident light wave, and totally reemit the energy as reflected light. Thus making the surface appears shiny.

金屬要經過打磨先會閃亮，好多人係做呢行，如果嫌打磨慢，可以電鍍一層鎳鉻合金亦可。

Regular Reflection.