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RichyB
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I don't understand, light is just a form of energy.
Why is it that I can see the things when light hits me in the eyes?
Why is it that I can see the things when light hits me in the eyes?
TheOtherDave said:That's what your eyes do... They sense energy in the form of EM radiation within a certain frequency range.
It's just a sensor doing its job.
RichyB said:But is it that the photons carry electrical information about the object it just hit and deliver it to our eyes?
TheOtherDave said:No, aside from the photon's frequency (color, since we're talking about vision), there's no transmission of information, electrical or otherwise. Photons just bounce around until they're absorbed by something... In this case that'd be a rod or cone in the back of your eyeball.
Yeah, that's about right.RichyB said:So the EM radiation changes depending on what it hits and that's how we see if something is red/blue.
It's just the frequency of the light. When a photon hits something, it'll either be absorbed, reflected, or pass through, depending on the properties of what it hits. Stuff that looks red, for instance, reflects "red" light and doesn't reflect the rest. You can get some pretty weird effects by shining colored lights on things that only reflect (or absorb) very narrow bands of light.RichyB said:And is something actually a colour or is it that, it's only that colour because of the frequency of the EMR? What is it about the object that changes the frequency of the EMR for it to appear that colour, is my question.
You're welcomeRichyB said:Thanks btw I'm new to this I appreciate you helping out someone who doesn't know physics.
RichyB said:So the EM radiation changes depending on what it hits and that's how we see if something is red/blue.
And is something actually a colour or is it that, it's only that colour because of the frequency of the EMR? What is it about the object that changes the frequency of the EMR for it to appear that colour, is my question.
Thanks btw I'm new to this I appreciate you helping out someone who doesn't know physics.
TheOtherDave said:No, aside from the photon's frequency (color, since we're talking about vision), there's no transmission of information, electrical or otherwise. Photons just bounce around until they're absorbed by something... In this case that'd be a rod or cone in the back of your eyeball.
Doesn't intensity come from how many of them there are? Hmm... maybe I'm thinking of something else.DragonPetter said:There is other information photons/EM waves gives us with regards to sight. For, example, intensity is an important piece of information light gives us that we can sense and use to know what the object the light came from was. Direction is another piece of information (also a factor in intensity) that light carries with it that we can interpret to understand what the light came from.
Yeah, but directionality, in the sense of the word that you're using, results from the interaction between the light and your eye (specifically, as you pointed, with the lens); it's not normally information that the photon actually carries. We're talking about how the eye perceives color here, not cutting-edge, causality-violating, quantum entanglement experiments.bahamagreen said:Actually, light does provide information about direction... in so far as the eye uses a lens and aperture to project onto the retina. The specific locations on the retina correspond geometrically with specific directions in front of the eye... so that when you have something sensed at a location on the retina, that corresponds to a point in your visual field, which also corresponds to a particular direction axis through the aperture, which also corresponds to the line between that point on the retina through the aperture to the direction from which the light originated.
RichyB said:It's weird the thought that, what we see isn't actually how the universe is, just how our eyes interpret it.
Like if our eyes evolved differently we'd have a completely different view of the universe init?
TheOtherDave said:Yeah, but directionality, in the sense of the word that you're using, results from the interaction between the light and your eye (specifically, as you pointed, with the lens); it's not normally information that the photon actually carries. We're talking about how the eye perceives color here, not cutting-edge, causality-violating, quantum entanglement experiments.
Light is necessary for vision because it is the source of all visible information. When light hits an object, it reflects off the surface and travels to our eyes, where it is then processed by the brain to create an image. Without light, there would be no visible information for our eyes and brain to interpret.
Light allows us to see colors because it is made up of different wavelengths, each corresponding to a different color. When light hits an object, the object absorbs some wavelengths and reflects others. These reflected wavelengths are then detected by our eyes, which send signals to our brain to interpret as colors.
Objects appear clear and in focus because of the way light is refracted by the lens of our eye. The cornea and lens work together to focus the incoming light onto the retina, which contains light-sensitive cells called rods and cones. These cells convert the light into electrical signals, which are then sent to the brain to create a clear and focused image.
Light travels through different mediums, such as air, water, and glass, because it is made up of particles called photons. These photons are able to pass through most materials because they have a very small mass and do not interact with other particles in the medium. However, they can be slowed down or bent when passing through a denser medium, causing phenomena like refraction and diffraction.
Some animals see differently in different types of light because their eyes have evolved to detect different wavelengths of light. For example, some animals, like cats, can see in very low levels of light because they have a layer of tissue behind their retina that reflects light back through the retina, giving them a second chance to detect it. Other animals, like bees, can see in the ultraviolet range, which is invisible to humans, allowing them to see patterns on flowers that guide them to nectar.