I have a question on white light bending. I know that when white light hits a prism it turns into different colors because white light is simply all the visible light in a rainbow. My question is that why are the colors in the order they are in? In a rainbow, the colors are ordered as red, orange, yellow, etc. Why are the colors ordered that way?
Let's compare the perception of sound and the perception of light/color. I'm making that comparison to underline that in order to arrive at perception of color we do a lot of processing.
Our perception of pitch is pretty straightforward. When you hear two notes (after each other or together), you can hear which one is pitched higher. The place in the ear where mechanical vibration causes specific neurons to send signals to the part of the brain that processes hearing is called 'cochlea'. Depending on the pitch of the incoming sound a specific part along the length of the cochlea resonates with the sound, triggering corresponding neurons to send signals. It's all very one-on-one.
Light has in common with sound that it is a form of vibration, and it travels in waves. But its frequency is way too high for any biological structure to resonate with it. Instead the light-sensitive cells in the retina of the eye contain molecules that resonate with incoming light. That resonance is somewhat specific, but not as specific as in the case of hearing. Interaction with incoming light causes a change of the light-sensitive molecule, and the work that the retina-cell does to revert that change triggers it to send signals.
The eye has three slightly different light-sensitive molecules such that by comparing response to incoming light we get some sense of the composition of the incoming light.
The color we call 'red' is the color with the longest wavelength.
Prisms and water droplets are not the only things that affect the propagation direction of light. As light travels through the atmosphere it has a small probability of being scattered. The short wavelengths (the colors we perceive as shades of blue) are more prone to being scattered.
In the evening and in the morning the Sun is close to the horizon and the light has to travel through a lot of atmosphere to get to us. In general the composition of the light from the Sun is such that we will perceive that as white light. But with the atmosphere scattering the blue end of the spectrum, we often see the Sun having a red color when the Sun is close to the horizon.
The Sun gives us warmth, so naturally all us humans will associate the color we call 'Red' with warmth. Conversely, we will all associate absence of any hint of red (the blue colors) as comparatively cold.
We perceive Yellow as a particularly bright color, because we perceive incoming light as yellow when it has such a composition that it triggers two of our three light-sensitive molecules in about equal measure. Put differently: we perceive a mix of different colors of light as Yellow when it has the Red portion and The green portion of the spectrum in it, but little blue portion.
To get from light entering the eye to the perception of color by the visual cortex is a long way; it involves stages of processing information. It is remarkable that we experience different colors so vividly different, given that the perception of color is very much a constructed perception.
I suppose that our brain makes the different colors so vividly different by having specific strong associations. For instance, it seems to me that we will naturally associate the spectrum of greens that we perceive with the things around us that are predominantly green. It seems to me that these associations, not all of them conscious associations, allow us to feel a lot of distinction between the colors we perceive.
Your question, 'why are the colors ordered that way'.
One answer to that is that all humans have the same genes for a set of three different light-sensitive molecules, and the responses of the cells containing these respective molecules are processed the same by all humans, so you get for all people pretty much the same pattern of associations between colors and things like warm/cold, scents, flavors, etc. Hence for all people the pattern of associations, from one end of the spectrum to the other, will be the same.