Questions tagged [perception]

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Are radiance and luminance really independent of distance to observer?

Recently, I learned that apparently both radiance and luminance are independent of the distance between the light emitting object and the observer. The reasoning was that although the radiant/...
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1 answer
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How does curvature of our eye affect our perception of the world? [closed]

The front part of the eye which can allow light to enter is a bit curved, so shouldn't this cause us to see a curved distorted version of reality when it is really not there? Is there any way to ...
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2 answers
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Can we tell on which side of a lens an image appears?

Suppose I look through a single, thin, converging lens at an object on the opposite side. Depending on where the object is placed, the lens will either produce a real image on the side of the lens ...
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Theory for the relative scale of objects?

I've been pondering what Prof. Brian Cox said in an interview (still searching for it) where he said something along the lines of: we (human beings) are very small relative to the earth, universe. I'...
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Why can we hear instruments but not voices?

I've seen this graph: But I don't get something. Consider the 2kHz line (highlighted in red). This graph implies we can hear an orchestral instrument at 2kHz before we can hear a human at the same ...
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Blinking LED and the human eye/perception

When an LED is flashing at 2 times a second, the human eye can perceive the ON and OFF state. We can clearly see when the ON state is and when the OFF state is. When it is flashing 10,000 times per ...
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-1 votes
2 answers
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Does sound travel through FINGERS?

as we know that sound's speed is fastest in solid (and slowest in air). QUESTION - what is the reason when we close our ears and don't really hear loud noises though sound travels faster in solids?
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How to convert light energy received on surface to perceived brightness level?

I'm trying to understand (from a perception POV) the difference in the brightness levels of color as a function of light energy. By the inverse square law, the light energy falls by a factor of 4 if ...
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2 answers
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Black body radiation: why can it glow yellow?

With black body radiation, light of different wavelengths are emitted in various proportions depending on the temperature of the emitter. Graphs of spectral radiance vs wavelength for different colour ...
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1 answer
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Are we misunderstanding time? [closed]

I think time is a constantly and uniformly flowing thing made by us to compare and relate different events with each other by it. It help us to predict things at different points in this flow. It ...
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1 vote
1 answer
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Why objects dont appear closer and smaller to a myopic person and far and larger to hypermetropic person after wearing spects?

I am a myopic person, and wear a concave lens. It is taught to us that lens I wear help to form image on my far point and thus help me to see far object. 1.But we have also learn that concave lens ...
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1 vote
0 answers
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Can Consciousness be Understood as an Emergent Phenomenon of the Evolution of the Human Brain? [closed]

Straight question - is explaining (or at least understanding) consciousness in the realm of physics? Detailed question: We know that consciousness exists. Or rather, I know that I have it. The rest of ...
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1 answer
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Are there an infinite or finite number of colors (can we see infinity?) [closed]

Take any blue or red, mix in equal parts and you have purple. Now mix 50 units of red and add 25 units of blue for another purple, then 50 units of red and 12.5 units of blue for yet another purple ...
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Quantum Brain Dynamics (QBD)

I found an article that broach this matter, I wanted to know if this Quantum Brain Dynamics (QBD) is treated in the scientific environment with such seriousness or is it some kind of unfounded ...
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4 votes
3 answers
217 views

Is there a relationship between quantum physics and chaos theory on a classical scale?

Im a complete physics lay person and I read somewhere that chaotic systems are subject to tiny differences in initial conditions and that the brain is a chaotic system. Does that mean our thoughts are ...
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-1 votes
1 answer
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Why do I keep forgetting the physics I've learned? [closed]

I've taken quite a few physics classes over the years and I read about physics when I can. However, I always forget what I've learned. When someone talks about a concept, until I go review briefly ...
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1 answer
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Does brain activity generate anything outside our bodies? [closed]

I have been reading recently about the Law of Attraction and while I don't believe in its 'scientifical' basis it did make me think about whether our brain produces any kind of activity strictly ...
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1 vote
3 answers
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Perception of simultaneous events

I have a two-fold question about the light-cone structure of spacetime, specifically about space-like separated events. As far as I understand it, any two events that happen at the same time in a ...
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Spacetime distances and perception

My question is about how things appear in human perception vs how things are in spacetime. Take as an example my perception of the laptop screen while I am writing this. As far as I understand it, ...
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4 answers
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Why does an audio signal sound differently if we randomly flip gradients between each adjacent pair of samples?

Let's assume the samples of our audio signal are always in the interval [-1,+1]. When flipping all the samples (multiplying them by -1), listening to the sound ...
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1 vote
0 answers
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Resources on understanding the Orchestrated objective reduction

I was trying to understand the mathematics behind the theory of Orchestrated objective reduction, and clearly, first I read the original paper of Penrose & Hameroff. Then I tried some other ...
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7 answers
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How can we discern so many different simultaneous sounds, when we can only hear one frequency at a time?

As I understand it, the eardrum works like any other kind of speaker in that it has a diaphragm which vibrates to encode incoming motion into something the inner ear translate to sound. It's just a ...
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Why doesn't ice in a glacier feel as cold when I touch it as the ice I get from my freezer?

When I was in Iceland, I went to a tour in a glacier and I remember the ice that was there. It looked and felt like a huge amorphous block of glass: hard, smooth, not wet, and not that cold. Not as ...
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Why don't we perceive high pressure and low pressure areas as distinct in a sound wave?

I was watching this video when I came upon this question: wether it be high frequency or low frequency, sound waves are made of high pressure and low pressure areas (they are waves, after all). I mean:...
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Is the Big Bang occurring or did it already occur (a question about time) [duplicate]

I understand how time (space/time) is perceived according to the theories of relativity, but I still don’t understand: Did the Big Bang occur 13.8 billion years ago or is it occurring relative to us ...
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34 votes
11 answers
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Why can't the human eye focus to make blurry photos/video clear?

The human eye focuses by flexing the lens, changing its focal length. When we switch from looking at a near object to a far object, our lens flexes, moving the focal length such that the near object ...
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5 answers
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Why does the brain interpret light from a mirror the way it does? [closed]

When we place an object above mirror and viewed from side, we see the image to be below the object, as if the reflected light is coming from inside the mirror. From the image above, the light from top ...
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2 votes
1 answer
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Is the ear really phase insensitive?

If the ear is phase insensitive (Ohm’s Law of acoustics), and you listen on headphones, how can the brain hear a phase inversion on one channel of a stereo signal? I play bass guitar and practice on ...
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How we feel (perceive) exact size of object through our eyes?

Light after getting reflected from objects gets focused on retina by our lens. The images formed on retina is small, which is then sensed by our brain and depending on distance we feel size of that ...
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3 votes
5 answers
571 views

Would a navigator announcing ship velocity whle approaching lightspeed make linear announcements?

Given my admittedly limited understanding of relativity, I believe that as a hypothetical space ship approaches the speed of light at a constant acceleration, what the crew would "see" on ...
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1 vote
1 answer
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About parallel and intersecting timelike worldlines

Suppose that two straight timelike worldlines are (not) parallel with respect to some frame $S$. Will these worldlines remain (not) parallel with respect to any other system $S^{\prime}$ related to $S$...
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2 votes
1 answer
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Does the vanishing point of linear perspective occur when there's a 1-to-1 matching between the lights in the source, and the sensors of the observer?

Imagine we have a panel of lasers in a truly dark vacuum, together with a panel of sensors, facing each other, some distance apart. Further, imagine that the number of lasers within the light-panel is ...
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3 answers
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Why we only see black colour when there is no light? [closed]

pls help me on it. I do not know if it is right but why do we only see black colour while there is no light.
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1 answer
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Third Eye and how the brain would see the world [closed]

Let's suppose that through engineering, a third bionic eye would be attached to a human and interfaced directly with the brain. Let's assume this third eye is positioned in the middle of the forehead. ...
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9 votes
5 answers
2k views

How can we see objects with the help of light if we cannot see atoms?

We know that the objects are made up of atoms. We also know that we cannot see atoms with the help of light as the wavelength of light is too big in comparison to atom. So, my question is then: how ...
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3 votes
1 answer
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World of 2-dimensional beings [closed]

In a world of two-dimensional beings, How would a two-dimensional (A) being view another two-dimensional (B) being as? Would they always perceive each other as a straight line?
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1 vote
0 answers
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How do we see things? [duplicate]

What I mean is, suppose white light falls on a red object and is reflected, so when we see the reflected light reaches our eyes we see it as red (probably because its wavelength corresponds to red). ...
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5 votes
3 answers
366 views

How does brain perceive time dilation due to gravity?

Einstein's General Relativity says gravity warps spacetime. Consider a hypothetical scenario: A person travels into space from Earth. He landed on a different planet in some far off galaxy where time ...
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2 votes
1 answer
69 views

Why did a green light appear white when looked out of the corner of my eye? [closed]

The other day I saw a green light emitted from some source far away, and I realised that if I looked at it out of the corner of my eye I perceived it completely white. What is the explanation for this?...
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1 answer
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Why the color of light observed dark (almost no light) from section of overlapping of two different colored plastic sheets?

Two transparent plastic sheets say of red and blue color overlap as shown in figure . An observer looks at a clear sky through the sheets. He will observe light coming through sections as, SECTION 1: ...
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2 answers
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Why do we only see VIBGYOR colours from dispersion?

I read all the suggested duplicates and they seem to be addressing the relation between primary colours and VIBGYOR. But my straightforward question is when so many colours with different wavelengths ...
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2 votes
1 answer
106 views

What's the meaning of 'understanding' in physics? [closed]

I read this article which is on how Feynman thought of the difference between physics and mathematics. Feynman's point is that physics is to understand nature while mathematics is to make their own ...
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1 vote
3 answers
144 views

How does a spectrum analyzer works. Example with particular case: eyes [closed]

[edit]: I reformulated my question to first talk about general spectrum analyzer and then ask about how vision works (which is a particular case of spectrum analyzer as I explain below). Let's assume ...
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1 vote
1 answer
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How does one sound drown out another?

If I'm laying in bed at night with the fan on, I cannot hear nearby traffic. If the fan is off, I can hear the traffic. What is/are the principle(s) involved in this phenomenon?
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1 answer
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Is the total volume proportional to the number of identical sound sources? [closed]

What happens to the perception of loudness when 4 identical devices placed around the listener play a sound sample? Will they sound 4 times "louder" than 1 device? What if they're a bit out ...
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20 votes
11 answers
4k views

Are colors grounded in physics or are they a matter of human perception? [duplicate]

My father was colorblind, and I always wondered if colors were a matter of physics or if different colors are just a human way of describing and differentiating our visual perception of the world? ...
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0 answers
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Objects viewed across a body of water

I'm sitting on the back patio of my lake house, (looking across the lawn and across the lake) and viewing the mansion across the lake... But when I go next door (flat lot), the house looks larger/...
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0 votes
2 answers
157 views

What kind of information does light carry so that brain can "see" shapes and distances of objects? [duplicate]

I know that we actually see with our brain in a way that eyes only absorb the incident light upon them and they transform some sort of information to the brain and the actual "seeing" is done by the ...
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4 votes
1 answer
208 views

Can white light have two spectral peaks?

I was looking at a graph on the receptive ranges of the 3 types of color sensitive photoreceptors in us humans, and I had the idea that if we place only two peaks at the right places, we'll be able to ...
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0 answers
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Why don't cell phones pick up music in phone calls? [duplicate]

Why is it that a listener on a cell phone cannot hear music on the other end? For example, the source phone is located either in a car with music being played, or is at a concert. The listener hears ...
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