system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is glass transparent but other things are not? As in, why can you see through glass but not say a wall?
gpt
Light is not reduced to the light we, humans, can see. As a matter of fact X-rays, Ultraviolet, Infrared, Microwaves, Radio waves, Wifi are all different types of light and Visible light is just a portion of the whole spectrum. Transparency is not reduced to visible light. Your cells are transparent to X-rays but not your skeleton and that's how doctors can examine your bones. Walls are transparent to radio waves and wifi so that's why you can listen to radio without needing an antenna outside your home and connect to the wifi from any room of your house. It happens that glass is transparent to visible light so we can see through. 
Now, the reason why glass is transparent to visible light and walls are transparent to radio waves has to do with their atomic structure. It is kind of complicated for an Eli5 but it is a matter of interaction between atoms and light: if the atoms interact with a specific kind of light, it can't get through unscathed so it is not transparent to that particular kind of light. If there is no interaction then the light just goes through and the result is transparency.