system
Given the following post, respond as if you're commenting on Reddit:
human
What gives things color on a molecular level?
gpt
It has to do with how compounds interact with visible light. Colors occur when a substance absorbs or refracts specific frequencies in the visible spectrum, which depends on specific physical or electronic properties of the compounds that vary from compound to compound.

Since visible light is a rather arbitrary and narrow range, many compounds don't interact with it, therefore the "default" is to reflect all of the visible light (making it appear white) or allow all visible light to go through (making it colorless).