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Questions tagged [perception]

The tag has no usage guidance.

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1answer
31 views

How do we hear harmonics and how does it affect audio fidelity?

First and foremost, do we hear a sound wave as a sum of all the individual harmonics, at the fundamental frequency, or do we hear all the associated harmonics above the fundamental frequency and ...
-2
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0answers
44 views

Does the Sun appear further than it actually is because of atmospheric refraction?

The stars appear higher or more far because of the atmospheric refraction. The sunlight also suffer atmospheric refraction. So does the Sun also appear more far than actually it is?
0
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1answer
75 views

Why don't we see inverted image while wearing spectacles? [closed]

We know that the lens in our eyes forms an inverted image on retina and brain reverses it to give the correct image. But when one wears specs the image would get reversed twice so we should see things ...
72
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5answers
7k views

Why can we distinguish different pitches in a chord but not different hues of light?

In music, when two or more pitches are played together at the same time, they form a chord. If each pitch has a corresponding wave frequency (a pure, or fundamental, tone), the pitches played together ...
2
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1answer
121 views

How does the Many-Worlds Interpretation of Quantum Physics relate to Consciousness? [closed]

According to the Many-Worlds Interpretation of Quantum Mechanics, each quantum event causes the world to "branch" into a superposition of outcomes. How come "my" consciousness only chooses one of ...
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2answers
115 views

Why does physics “make sense”? [closed]

I was wondering if anybody had an explanation for why physics makes so much sense to us humans. In physics, many concepts just seem to make sense to me, but I cannot explain why. You may say that this ...
1
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2answers
151 views

How many eyes are needed to see a four-dimensional world? [closed]

If a four-dimensional world were to exist, how many eyes would a creature minimally need to see it (in three dimensions)? Three? Four? (Bonus question: how should these eyes be spatially configured?)...
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1answer
39 views

EM spectrum and sense of sight

If we cant see all the spectrum does this mean that maybe exist objects we cant perceive? or it just the colors we cant perceive?
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2answers
40 views

Perception of curvature of human eye [closed]

How are human eyes able to detect the different curvatures of surface ? Basically how are the human eyes able to differentiate between a plane surface and a convex or a concave surface?
56
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6answers
8k views

How does light combine to make new colours?

In computer science, we reference colours using the RGB system and TVs have pixels which consist of groups of red, green and blue lines which turn on and off to create colours. But how does this work?...
3
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2answers
202 views

Why might Roger Penrose argue that Godel's incompleteness theorem(s) suggest that consciousness is non-algorithmic?

This past March, when I called Penrose in Oxford, he explained that his interest in consciousness goes back to his discovery of Gödel’s incompleteness theorem while he was a graduate student at ...
0
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1answer
59 views

Why can't our cognitive sense or five senses sense or fathom hyper-dimensional spaces? [duplicate]

Why can't our cognitive sense or five senses sense hyper-dimensional spaces? Is it because of the way our human body is built?
2
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1answer
119 views

Why do I see discrete images when moving an object in front of a screen? [closed]

I observed this while doing my homework. I have a habit of shaking my pen between my fingers vigorously while thinking something. My PC's screen is right in front of me (on my study table itself). ...
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2answers
65 views

Tiny blue and red paint close to each other result in black or magenta? [closed]

Now, if I draw two tiny spots with red and blue paint on paper and they are so close (but they do not cover each other) to each other that human eyes cannot identify there are two spots. To the color ...
1
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1answer
54 views

How is the subjective loudness of sound computed?

The intensity of a sound is a measure of the energy that the sound waves carries through space per unit time per unit area (since energy is conserved along the wave unless work is done on/by it and ...
2
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1answer
64 views

Why are the active noise cancellation headphones subjectively better in reducing “periodic” noise?

According to experience of mine and of my friends using active noise cancellation headphones, the technology is much more efficient in reducing "periodic" noise, such as humming of jet engine, fridge ...
0
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1answer
57 views

Why we see a static picture of the sea when we are traveling by plane?

This question may look stupid but it's something that came to my mind months ago when I was on a plane. When one looks through the window on a plane, there are light and dark parts of the ocean (it's ...
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0answers
28 views

How can we determine time flows in one direction? [duplicate]

Suppose that time could flow in either direction, forward or reverse, similar to a movie. How could our brain possibly record that time had moved backwards? Would there be any way to tell if time had ...
3
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1answer
353 views

Do we hear anything special when the beat frequency is in audible range, but the sounds producing the beats are not? [duplicate]

When the beat frequency is very low, we hear periodic maxima and minima. Our ear cannot perceive a on-off like sound when its frequency is more than 10 Hz. So, beat frequency in audible range will not ...
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0answers
19 views

What is the most important data when measuring the 'sources' from which we perceive light?

If the JND of light for our eyes in it's most sensitive areas is easily 5nm or less, when measuring light sources, which data should be most pertinent? For instance, the attached measurement of an ...
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0answers
50 views

What causes observed color differences in white LED's for near and far fields?

While running towards traffic early morning before sunrise I recently noticed that the new automobile LED (white) lights when viewed at a distance appear blueish, but when the light is viewed much ...
5
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1answer
174 views

Why do we experience a slice of time, but not a slice of space? [closed]

I (and every one I guess) perceive space as an extended region where things happen. In contrast, time is perceived as a lucky of slice. Also in space I can choose in which direction I want to move, ...
2
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1answer
66 views

Why doesn't the brain flip retinal image horizontally as well?

I was reading about the Camera Obscura and the physics of apertures, and I read that "The camera obscura produces a flipped (horizontally) image as well as an inverted (vertically) one." I understand ...
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3answers
94 views

What is Fourth Dimension?

Before people get pissed at me for asking a question that has likely been asked more than a few times, I just want to know a simple answer, if first dimension is that an object exists, (collision) ...
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2answers
62 views

Defocusing the eye and computer monitors

Im not sure whether this is the right site to post this on, but here goes : We are often told to relax our eyes when using computer/tv screens for extended periods of time. I often find that I forget ...
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2answers
113 views

How to define white color scientifically? [duplicate]

I'm sorry some of you may mark this question as duplicate, but even though I searched over about this I couldn't get satisfacory answer. Also I think this question is more related to biology, but I ...
9
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2answers
301 views

Why does the moon appear fairly flat to a naked eye?

When I look at the regular ball picture the "edges" appear somewhat darker. Here's a random image I just found on image search :) Image source and that's how I can tell it's "round". Or so I assume. ...
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1answer
87 views

Is visible light really visible? [closed]

As we know, colors only exist in the brain. How can we see light if it has no color? Our eyes detect light, but seeing occurs in the visual cortex. Is visible light really visible?
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1answer
63 views

What limits the electromagnetic radiation we can see? wavelength or frequency?

Can we only see electromagnetic radiation that has certain range of frequencies and a certain range of wavelengths?
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3answers
105 views

Travelling at a speed faster than light [closed]

Imagine yourself to be bat. You cant see anything. You don't have eyes. All you can do is echolocate, using ultrasound. Now imagine something is moving away from you faster than the speed of sound. ...
5
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3answers
283 views

How does the human ear guess the source of the sound?

Suppose a sound is produced behind you. You can easily tell that the sound came from behind. Our ear lobes face towards the front and hence traps the sound waves which come from the front. Yet, we ...
2
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2answers
49 views

If someone were to put really small objects 10x spaced on a background, would they see the objects or the background?

If someone were to put a sheet full of 1 micron x 1 micron black squares as a grid on a white piece of paper, and spaced them 10 microns apart (up-down, left-right, obviously diagonal doesn't count), ...
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0answers
40 views

Visualizing in more than 3 dimensions [duplicate]

I'm not sure this is the right place for asking this question, but I would like to know the physics point of view concerning the limitations of visualizing in more than 3 dimensions. So why can we ...
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3answers
3k views

Why does the Sun appear larger during the sunrise and sunset?

Why does the Sun appear larger during sunrise and sunset compared to its size during midday even though its distance from the Earth remains fixed all the day? It is only during the Winter when the Sun ...
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1answer
382 views

Is a human thought merely energy that is changed from one form to another? [closed]

Einstein: "Energy cannot be created or destroyed, it can only be changed from one form to another." Is a human thought merely energy that is changed from one form to another?
1
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1answer
107 views

Why do objects that are further away seem closer? [closed]

I am outside and am walking to my house from my car that is across the street. I get in my house and look out the window and my car seems like its right in front of my window. Why is that?
1
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1answer
118 views

If our eye lens and cornea were flat would we still receive the world upside down?

Usually the effect of a pinhole (or camera obscura) and the lens of our eyes are creating the world upside down on our retina. Now imagine the lens and cornea would be flat is the pinhole effect ...
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3answers
90 views

Can light be stopped after being perceived?

Please note the following sentence before you answer the question: you may assume the light itself is not affected by the observer perceiving the light. Imagine the following schematic: A = Source B ...
88
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4answers
12k views

Why does a yellow object turn white under a yellow light? Shouldn't it turn yellow instead?

Recently I was eating a yellow rice for lunch in a restaurant with only yellow lights. But the rice looked white! I was intrigued by this because I always thought it should look yellow since the ...
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0answers
24 views

Inverting Horizon?

everyone knows that looking at the horizon at something going far away, the last thing you see from it is its top, but what if you had a ground going up very very very slightly and something moves ...
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2answers
85 views

LED headlight illusion

Commuting today, I noticed that the car behind me had LED headlights that appeared to "bobble" within their lenses--in other words the reflection of the car and the reflection of the headlight lamps ...
3
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4answers
255 views

Do our ears (or brain) only perceive periodic disturbances?

Through a little time spent using sound editors for this and that, I've come to notice that if I play any musical note 440 times per second, I hear an A, whose frequency is 440Hz. Then I tried with ...
3
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3answers
3k views

Difference between note and tone: which one has only one frequency? [closed]

What is note and tone both in physics and musical terms? Are the two used in different ways in the different fields or are they the same thing. Moreover, which one has only one frequency? Well this ...
16
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5answers
5k views

Musical notes and colors of a rainbow

I have wondered that in an octave in piano there are seven primary notes, and also we observe mostly seven primary colors of a rainbow. I know we perceive logarithmically, that means we only care ...
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0answers
68 views

How does the flicker fusion threshold prove time perception?

The flicker fusion threshold allows us to see when an animal can distinguish a flash of light and when they can only see a solid light. They have proven flies can see the light flicker at almost 240hz ...
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0answers
61 views

Is the perception of time absolute? [closed]

If there is a place where no changes or movements can be observed, can the time be perceived there?
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1answer
127 views

How dark is our universe(space) to us?

Yesterday I made a few photos from ISS and then made this aweseome gif out of them. If one would go out at night, where are no disturbances of city lights, one would see a bright, black, starry sky ...
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2answers
87 views

Listening to an aperiodic inverse sound wave

During the operation of noise canceling headphones, an inverse signal to the ambient noise is generated and is played through the speaker where every compression of the ambient noise is a rarefaction ...
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3answers
178 views

If color is just reflection of light, then can someone's purple look red to others?

If color is just reflection of light, then can someone's purple look red to others? Can anyone lend me a hand here? I always wanted to know this.
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1answer
181 views

Does the perception of time depend on the Mass/Height of the Observer?

Okay. We were discussing the following thing at work. Situation: Imagine a high building. If it falls sideways, it takes a lot of time in our perception. Now imagine something MUCH smaller. If we ...