B Why are things the color they are?

[Kyran]

TL;DR

I've heard certain wavelengths are absorbed and some are reflected by different things but what causes that?

I have not noticed anything in common between all things that are the same color. It must be something on the atomic level but if I look at the periodic table I see no pattern in how things behave and what their color is. So how can the sun be the same color as a highlighter and plastic the same color as jeans when they are made of very different things? I'm a high school student so chances are you'll have to explain this in your version of lamense terms.

 

[sophiecentaur]

Forget the Physics of how matter interacts (emits / absorbs / reflects etc.) light of different wavelengths. This is a separate issue from colour vision.

The answer to your question is that your eyes are not spectrometers; many different combinations of wavelengths are perceived as the same 'colour' because our analysis is, in fact very crude. Colour TV works because of this. An object that the camera records will have a spectrum which the camera (mimicking your eye) analyses (filters) into three values which are related to the familiar RGB values. The electronics takes these values and adds them in a complicated way. A new set of (actual this time) R G B values are fed to the red, green and blue LEDs of the display. When the system is working correctly, your eye will 'see' the colour of the image as being (very nearly) the same as the 'colour' of the original object.
Colour TV systems would never get away with such a simple colour reproduction method if our eyes were, in fact, any smarter.

Near enough is good enough.

 

[PeroK]

Summary:: I've heard certain wavelengths are absorbed and some are reflected by different things but what causes that?

I have not noticed anything in common between all things that are the same color. It must be something on the atomic level but if I look at the periodic table I see no pattern in how things behave and what their color is. So how can the sun be the same color as a highlighter and plastic the same color as jeans when they are made of very different things? I'm a high school student so chances are you'll have to explain this in your version of lamense terms.

There should be quite a lot online about this. E.g.

https://www.zmescience.com/science/physics/what-gives-colour/

 

[anorlunda]

I think transparency is a more interesting an more mysterious question than color. If you are interested in an introduction to why some things are transparent and others are not, try this:

https://en.wikipedia.org/wiki/Transparency_and_translucency#Absorption_of_light_in_solids