What determines what light is reflected back creating colors? I know color is reflected light, but what determines that? Does it have to doing with

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The frequency of the electrons? Idk

In: Physics

Not sure about the reflected light part, but the human eye mainly sees in 3 colors: Red, Green, and Blue. Any other color the eye can see is a mixture of those 3 colors. I’m not an expert so maybe someone can correct me.

Close! Frequency of the photons of light. Sources of light often emit a wide range of frequencies. The sun, for example, emits a full spectrum of frequencies extending beyond the visible spectrum. Things that light hits will reflect or absorb some of those photons depending on the properties of the molecules they hit and what it does to the molecules’ electrons when hit.

There is two pretty separate things.

One is purely physical, if the surface of something has many small features it just physically interacts with the light waves. If the surface has lots of small holes the light waves bigger than the holes and the ones smaller than the holes will reflect different ways and amounts. Butterfly wings are often shiney and colorful because they have tiny scales that reflect some colors to the sides and colors like blue outward.

The other effect is that the way things reflect is an atom absorbs it and then releases it back in the other direction. The wavelength of the light depends on what the electrons are doing and different configurations will put out higher or lower frequencies when you push energy into them

Yeah kind of related to the frequency of electrons. Think of atoms as electron motels, and the price of each room (orbital) is the energy paid when an electron rents a room or upgrades to a nicer room from a worse room.

As you shine light on something you send energy to the guests and fill the rooms or let guest upgrade rooms. Different amounts of energy are absorbed, corresponding to different frequencies of light that don’t get reflected back to you.

Your eyes see what is reflected and not absorbed by a guest electron, and that creates color in your mind.

Each color of light has a particular energy. Some ingredients in some substances have the ability to absorb energy that is in the range of certain colors. Which energy levels these are is very complicated and would be hard to predict just from knowing the ingredients. The same ingredient in different substances can absorb different energies (and therefore different colors).

(That is my ELI5 version. If this were r/askscience, I would talk about non-bonding d-orbital electrons and such)

Source: used to teach this stuff to Mineralogy students.