Chase

I know this may seem like a stupid question, but trust me it's not. Here's why I'm confused: it seems perfectly fine to look off toward the sun so that it lies in your peripheral vision, but based on what I know about vision, this still means that an image of the sun is being projected onto your retina.

The reason your peripheral vision is blurry isn't because the cornea and lens can't project sharp images there, but more due to the fact that there are very few cones in this part of the retina and consequently no sharp vision. But the fact remains that an image of the sun is projected on the retina, so why doesn't it burn the retina? Why is it safe to look toward the sun, but not at it? Isn't the only different where the image of the sun is projected?

Can we not look at the sun simply because the fovea is more likely to get burned than the rods in the rest of the retina? What's going on? Frankly I'm completely surprised that we can even look toward the sun without being blinded in our peripheral vision.

I know this may seem like a stupid question, but trust me it's not. Here's why I'm confused: it seems perfectly fine to look off toward the sun so that it lies in your peripheral vision, but based on what I know about vision, this still means that an image of the sun is being projected onto your retina.

The reason your peripheral vision is blurry isn't because the cornea and lens can't project sharp images there, but more due to the fact that there are very few cones in this part of the retina and consequently no sharp vision. But the fact remains that an image of the sun is projected on the retina, so why doesn't it burn the retina? Why is it safe to look toward the sun, but not at it? Isn't the only different where the image of the sun is projected?

Can we not look at the sun simply because the fovea is more likely to get burned than the rods in the rest of the retina? What's going on? Frankly I'm completely surprised that we can even look toward the sun without being blinded in our peripheral vision.

I can understand how glasses work, since they are pieces of plastic or glass that can shaped to be convex or concave, but how do contact lenses work? They all seem to just be thin meniscus type lenses, so how do nearsighted contact lenses, for example, work? Are these lenses actually concave even though they look like thin meniscus lenses?

And how do such thin lenses achieve the same affect as much thicker glasses since they're so thin?

I looked at my enlarged pupils in the mirror of a dark bathroom, but I noticed that there was less space between the top of the pupil and the sclera than the bottom of the pupil and the sclera, effectively making the pupil off center. Is this normal, and is there nay reason why the pupil would not be centered in the iris?

I heard that you can see total internal reflection in a simple glass filled with water. The sides will look silvery and reflective and you can't see anything past them, but if you put your fingers on the glass you can suddenly see your fingerprints because of frustrated total internal reflection where the light reflects off of your fingertips.

Is this true? Because if so, why does this effect only occur when the glass is filled with water? Doesn't total internal reflection occur when light goes from a high refractive index medium (glass or water) to a lower one (air)? If so, that means that total internal reflection occurs at the glass/air boundary, not the water/glass boundary, yet visible total internal reflection only occurs when the glass is filled with water, why is that?

Also, I have a red laser pointer, and I tried to observe total internal reflection by point it at a thick single pane glass window at various angles between 0 degrees and 180 degrees, and no matter what angle I chose, the laser always refracted through the glass with no total internal reflection. What's going on, why isn't total internal reflection happening?

In a healthy individual who is not under the influence of any substances, can each pupil have a different size, or are they always the same? For example, if both eyes are open but one is covered so it is in the dark, does the pupil of that eye enlarge while the pupil of the other eye stays small, or do they both change size so that they're equal in size but the size they show is the average of what both pupils "want" to be at, or are both pupils the same size?

If they're both the same, then which size is the size they end up being: that of the pupil in the dark, that of the pupil in the light, or an average size in between the two?

I'm interested in what causes and what happnes during total internal reflection of light, but even after doing some research I still don't understand a few things about it:

1.) What actually causes total internal reflection to occur in terms of how light interacts with the electrons at the boundary between two media? Why don't the electrons transmit light from a medium with a higher refractive index to a lower one, but they do for the passage of light from a medium with a lower refractive index to a higher one? Why do the electrons behave like this?

2.) What is frustrated total internal reflection, and how is it not a violation of conservation of energy?

Supposedly, during total internal reflection, even though the entire incident wave is reflected back into the originating medium, there is some penetration into the second medium at the boundary, resulting in an evanescent wave created across the boundary surface. This happens because Maxwell's equation don't allow for a sudden discontinuity in the field. First of all, how did he know that? And second of all, if there is field in the second medium, how can no energy flow across the boundary.

3.) According to a cited source on the Wikipedia article for total internal reflection, "the velocity of transfer energy of the transmitted electromagnetic field in the optically thinner medium can exceed the light speed c of vacuum." Isn't this impossible, isn't this a violation of relativity? How can this be?

Thank you so much, these are really tricky questions that I'm really interested in finding the answers to.

I've looked into 3-chip cameras, but no where is it explained how they really work. So I have a few questions:

1.) If the chips in a camera picks up only red, green, and blue, then how do they pick up colors like yellow and orange? I know about how additive color works where green and red make yellow, but how is yellow light actually sensed in a 3-chip camera? For example, in a 3 chip design with a prism that separates the incoming light only into red, green and blue, sending those to dedicated sensors that only pick up red, green, or blue, what happens to the yellow and orange, how are those colors picked up if they're not even split by the prism?

2.) In today's displays, a single pixel consists of only 3 subpixels, red, green and blue, but in a 3-chip camera the combined image produced by the 3 chips will mean that each pixel with have 9 subpixels, right; 3 for red, green and blue? Or do the individual sensors for each color have only one subpixel per pixel?

3.) On a semi-related note, I noticed that that cheap camcorders often have high levels of optical zoom (78X on one model I saw), while more expensive models generally only have 20X and below optical zoom. Why is that? And why do fixed zoom lenses generally not go above f/11, why others do?

I often hear that larger mirrors are used in telescopes in order to collect more light, in order to create brighter images, but this doesn't fit with observations of non-telescopic mirrors. Objects don't look brighter in bigger mirrors than smaller ones, so why would bigger mirrors in telescopes create brighter images?

Also, why is it that refracting telescopes have fallen out of favor and instead most advanced telescopes today are reflecting, but for camera lenses refracting lenses are preferred to reflecting ones?

I know that hi-8 video cameras used analog tapes to record and store video, but how was the video information actually captured? Was it with a CCD or something that just sent the analog information to the tape before being digitized as in min-dv? How did hi-8 video cameras actually work?

Also, I've looked up how VCR's and tapes work, but no where does it say how the little metal drum with the lines in it actually read from/records onto the tape. So how does that little metal silver drum do it?

Thank you.

I've looked into refraction and diffraction of light, but there are a few things that I don't understand, if you know any of the answers to these questions, please help me:

1.) Why does light bend when it slows down instead of just continuing on in the same direction after being absorbed, held, and then emitted by the electrons in the medium?

2.) Why are different wavelengths of light refracted to different degrees? I know it's because different wavelengths are slowed to different degrees, but why? Why does one wavelength travel slower than another?

3.) What's the difference between a dispersive medium and a non-dispersive medium? Why can some materials slow light down without being dispersive?

4.) How is it possible for the colors of a rainbow to be so pure? Given what I learned about the light paths for different colors in a rainbow, I know that red light is not only refracted at the angle where red is seen in a rainbow, but also at all the other angles. Given this, it means that, while green light is not refracted at the top of a rainbow where red is, red happens to be refracted where green is... which should mean that we would not be able to see any of the colors in a rainbow except for red and whatever the combination of red and all the other colors turns out to be. Yet we don't, why not?

5.) I have a similar question for the diffraction of light by a diffraction grating. If each color is diffracted at a different angle, it makes sense that a spectrum should be produced, but then I realized that each color is not just diffracted at one angle, but multiple ones, making a pattern of alternation bands of color and darkness... yet we don't see this when white light is diffracted by a diffraction grating, only for monochromatic light, why?

Thank you so much!

I have a few questions about vision and the eye that I'm trying to understand, since it seems that we shouldn't be able to see as well as we do:

1.) Why is peripheral vision blurry? Is it simply because there aren't any cones in this area of our visual field, or is it because light isn't actually focused there by the cornea and lens?

2.) Is there any functional reason that has been discovered as to why the fovea is not aligned with the optical axis of the eye, but rather at an angle to it? Shouldn't this mean that light isn't focused as much on the fovea as on the area next to it which is in line with the optical axis of the eye?

3.) Is there any reason why the retina doesn't extend over to cover the surface of the optic nerve?

4.) If the lens of the eye has different refractive indices in its different layers, doesn't this introduce aberrations since light isn't all focused the same amount?

Thank you so much, I really appreciate your answers!

I know a bit about digital cameras, but I have a few questions that I would really love to kno the answers to:

1.) If camera sensors only sense red, green, and blue, then how do they pick up colors like yellow and orange? I know about how additive color works, but, for example, in a 3 chip design with a prism that separates the incoming light only into red, green and blue, sending those to dedicated sensors that only pick up red, green, or blue, what happens to the yellow and orange, how are those colors picked up if they're not even split by the prism?

2.) Why is it that cheap camcorders often have high levels of optical zoom (78X on one model I saw), while more expensive models generally only have 20X and below optical zoom?

I am trying to understand electricity and I have two questions about it:

1.) If electricity is a flow of electrons, how does it power things? Here's a simple example of what I'm trying to understand: in a simple circuit consisting of a battery and a small light bulb, the charge difference between the two ends of the battery causes a flow of electric current when the two ends are connected in order to balance the charges. If a light bulb is placed in between them, the electric current interacts with the light bulb on its way from one end of the battery to the other, powering the bulb and lighting it up. But what happens to the elctrons after they have given up energy to the bulb? Once they pass teh bulb and reach the other battery terminal, aren't they no longer able to balance out the charge? Basically, what's going on, how does a flow of electrons power something without the action of powering something impeding the process that caused them to flow in the first place?

2.) When dissimilar materials are rubbed together, how is it that electric charge builds up on one of them? Does that mean that the atoms in that object temporarily becomes ionic, do the electrons become a pat of the atom's electron shell temporarily before being released, or do they just sit on top of the atoms in some way? What actually happens to cause static electricity?

I used to think that, since the human eye has three cones, red, green, and blue, that displays work because they use red, green, and blue pixels which correspond to the cones in our eyes. But recently I read that this is only an approximation, since the eye doesn't actually have blue cones, but rather violet ones. So then how is it that RGB displays can actually work and we perceive colors from them correctly?

Also, if we have way more green cones in our eyes than violet, why is it that darkness seems blue like in movies, rather than green? Supposedly night vision goggles show everything in green because we see green better than any other color, and we're more sensitive to it, so what explains the Purjinke effect?

I am not stupid, and I understand intuitively why things in the distance look smaller, but I can't seem to understand it conceptually. So why exactly is it that:

a.) Distant things look smaller?

b.) Parallel lines converge in the distance?

I have a few questions about vision and the eye that I'm trying to understand the answers to:

1.) Why is periferal vision blurry? Is it simply because there aren't any cones in this area of our visual field, or is it because light isn't actually focused there by the cornea and lens?

2.) Why isn't the fovea aligned with the optical axis of the eye, but rather at an angle to it?

3.) Why does the optic nerve create a blind spot? Is there any reason why the retina doesn't extend over to cover the surface of the optic nerve?

Thank you so much, I really appreciate your answers!

I've looked into refraction and diffraction of light, but there are a few things that I don't understand, if you know any of the answers to these questions, please help me:

1.) Why does light bend when it slows down instead of just continuing on in the same direction after being absorbed, held, and then emitted by the electrons in the medium?

2.) Why are different wavelengths of light refracted to different degrees? I know it's because different wavelengths are slowed to different degrees, but why? Why does one wavelength travel slower than another?

3.) What's the difference between a dispersive medium and a non-dispersive medium? Why can some materials slow light down without being dispersive?

4.) How is it possible for the colors of a rainbow to be so pure? Given what I learned about the light paths for different colors in a rainbow, I know that red light is not only refracted at the angle where red is seen in a rainbow, but also at all the other angles. Given this, it means that, while green light is not refracted at the top of a rainbow where red is, red happens to be refracted where green is... which should mean that we would not be able to see any of the colors in a rainbow except for red and whatever the combination of red and all the other colors turns out to be. Yet we don't, why not?

5.) I have a similar question for the diffraction of light by a diffraction grating. If each color is diffracted at a different angle, it makes sense that a spectrum should be produced, but then I realized that each color is not just diffracted at one angle, but multiple ones, making a pattern of alternation bands of color and darkness... yet we don't see this when white light is diffracted by a diffraction grating, only for monochromatic light, why?

Thank you so much!

The clearest glass will cast a definitely recognizable shadow in the presence of a light source. Why is this so and how can this be? Certainly the 7% of light reflected from the surface of the glass can't account for the darkness of the shadow cast by the glass, right?

If the light emitted from a light bulb comes from the movements of the electrons in the tungsten filament, then that means that the amount of light coming from a light bulb is limited by the amount of electrons in the material, right? And while I know that there are millions of electrons in a light bulb filament, certainly there are more electrons on the surfaces of a room illuminated by a light bulb than the number of electrons in the filament.

So if we only see things because the electrons in them reflect light back to our eyes, then how can a single light bulb give off enough photons to illuminate an entire room? In a given instant, the amount of electrons on all of the illuminated surfaces in a room is greater than the amount of electrons emitting light in a light bulb, yet we see everything... how can there be enough light for this to occur?