Does air pollution contribute to the blueness of the sky (make it bluer)? Has th…

Does air pollution contribute to the blueness of the sky (make it bluer)? Has the sky become more blue with the advent of technology (factories, machinery, etc.)?

Yes. Pollution does tend to make the sky bluer and the sunsets redder. However, pollution also imparts colors directly by absorbing certain wavelengths of light. The orange haze that hovers over cities is often caused by nitrogen oxides, which are simply orange in color and act like pigments to make everything appear orangish. However smoke and dust certainly change the look of the sky by increasing scattering. Natural disasters are even more effective: volcanic eruptions create the most beautiful sunsets of all by tossing vast amounts of dust into the air.

Why is it any worse to observe a solar eclipse rather than a normal glimpse at t…

Why is it any worse to observe a solar eclipse rather than a normal glimpse at the sun?

The problem with looking at the sun during a solar eclipse is not that it is somehow brighter than normal but rather that (1) you tend to stare at it and (2) the size of its bright region is reduced so that it doesn’t hurt as much to stare at it. It’s hard to stare at the full sun because it feels uncomfortable but looking at a tiny part of the sun may not feel bad enough to make you avert your eyes. Nonetheless, that tiny part of the sun can cook your retina and cause permanent damage.

If white color has a reflection close to one, what role does shininess or dullne…

If white color has a reflection close to one, what role does shininess or dullness play?

Just because two materials both reflect all of the light that strikes them doesn’t mean that they look the same. When you send a flashlight beam at a white surface, you can see that reflected light from all directions. When you send the flashlight beam at a mirror surface, you can only see the reflected light from one particular angle. Both the white surface and the mirror surface reflect virtually all of the light that hits them. A shiny white surface is different from a dull white surface because a shiny white surface has a small amount of mirror character to it: you can see the whiteness from any direction but there is also a mirror aspect that you can only see from certain angles.

Why can water appear brown, blue (as in the ocean), and clear (as in a glass of …

Why can water appear brown, blue (as in the ocean), and clear (as in a glass of water)?

Brown water contains colored contaminants that provide the color. Brown is the typical end result for a random mixture of pigments. The blue ocean is caused mostly by the sky. Since the ocean reflects some of the light from the sky, it appears blue. Pure water is almost completely colorless. Thus a glass of water has no color (unless you illuminate it with colored light). But if you look at a white light through many meters of water, that light will become slightly colored. Water absorbs a very small amount of visible light and you will see only what is not absorbed. I’m not sure what color pure water has. It may appear slightly green.

Does red or blue light bend more in glass?

Does red or blue light bend more in glass?

Blue light almost always bends more than red light because blue light almost always travels more slowly through glass than does red light. This phenomenon is known as dispersion However, there are some glasses that exhibit anomalous dispersion, where red light travels faster and bends more than blue light. Anomalous dispersion only occurs when there is a resonant absorption of light in the glass, typically because of some impurity atoms or ions in the glass or because of some transition that occurs in the glass itself. While the resonance will only absorb light at one particular wavelength, it alters the propagation of light at nearby wavelengths. At wavelengths just shorter than the absorbed wavelength, light travels anomalously fast through the glass so that it bends less than light that is somewhat redder in color.

Why is it that after swimming in a heavily chlorinated pool, you can see the spe…

Why is it that after swimming in a heavily chlorinated pool, you can see the spectrum around lights?

Your eye works very hard to keep all of the different wavelengths of light together so that they can form sharp images on your retina without any color errors. If you look at a white light bulb, all of the different colors from that bulb must arrive together on your retina or else you will see colors where they shouldn’t be. Keeping these colors together is no small task and is one of the biggest problems encountered by lens makers for cameras and telescopes. The chlorine in a pool evidently upsets your eye’s ability to control these color errors. However, I’m not sure what goes wrong or why chlorine causes this problem.