Why can we see through glass???

Answer 1

Light is an electromagnetic wave. These waves interact with the atoms and molecules when they go through a substance. If the energy of the electromagnetic wave gets absorbed by the atoms the substance appears opaque, if the atoms cannot absorb the energy the substance is transparent.

The reason for that different behavior is unfortunately not easy to understand, actually it is a quantumechanical effect. You may have heard that on very short scales (atoms for example) energy is not a continuous quantity, but can only be absorbed or emitted in packets, which gave the theory it's name: These packets are called quantums.

Different materials can absorb different quantums of energy, and the energy of an electromagnetic wave is related to it's wavelength, which we see as it's color if it's visible light. So glass can't absorb energy of visible light and it simply (well, not that simple ... ;) ) passes through it.

Water for example is also transparent for visible light, but absorbs almost all other wavelengths, so probably this is the reason why our eyes are sensitive for that range of wavelengths: Our eyes developed during evolution in a stage where our forebears lived under water.

Answer 2

Believe it or not, glass is really a liquid.

A veeeerrrrryyyy slow moving liquid.

Answer 3

Because there is no color added, it is transparent. Don't mess with me my whole family worked at a glass factory years ago.