Questions tagged [perception]

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2answers
2k views

Can you hear vibrations through your bones?

If we have a source, like a speaker, but with no sound and only the vibrations, and this vibrations were transported to a surface which you can put your elbows on it and then put your hands to your ...
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4answers
4k views

Can we see sound with our eyes? [closed]

Is there a type of sound within our visual spectrum that we can see with our eyes?
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2answers
5k views

Why can't the human voice produce a Shepard tone?

Audio of a shepard tone on youtube. So what is a Shepard tone? A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played ...
6
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1answer
319 views

How is the perceived quality of sound measured and analyzed?

I am doing a physics experiment researching the effect of temperature inside the clarinet pipe on the quality of its sound. I know that the speed of sound is directly proportional to temperature of ...
76
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8answers
8k views

Does quantum mechanics play a role in the brain?

I'm interested in whether the scale of processes that occur in the brain is small enough to be affected by quantum mechanics. For instance, we ignore quantum mechanics when we analyze a game of tennis ...
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2answers
328 views

Speed and multiple images

Why an object (or something else) create multiple images of itself when it is moving fast? An earphone spinning in circle for example.
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2answers
19k views

How many frames can human eye see? [closed]

What's the limitation of our eyes? Can we differentiate 60fps from 120fps? Are new 144hz monitors just a marketing trick? Couldn't find any proper journals or studies about the matter.
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1answer
88 views

Literature on scientific achievements in physiological acoustics after Helmholtz [closed]

I'm greatly interested in theoretical/mathematical/physiological aspects of music and the corresponding acoustics. As everyone knows, the Greek already discovered that consonant sounds seem to ...
-1
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1answer
9k views

How fast would you have to run to create a mirror image? [closed]

So I was watching The Flash and in the most recent episode he runs so fast that he is able to create a mirror image of himself so that it looks like there is more of him than there actually is. So I ...
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5answers
902 views

Perception of Depths and Stereovision [closed]

I watched a video on Youtube and read a few articles which say that human beings see 3D because we have two eyes. But does that mean when I close one of my eyes, I should see 2D? It doesn't happen so. ...
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1answer
333 views

Our Perception of Heat [closed]

Our body temperature is roughly 37 degrees celsius (that is, when we measure our body temperature externally, by using a thermometer that measures the temperature of our skin usually between our arm ...
-2
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1answer
131 views

Imagine a new color. Imagine a new physical quantity [closed]

It is well known, that a human being can not imagine new colors which are not obtainable by just combining the already known ones (red, green and blue). Actually I can draw parallels to physics and ...
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1answer
67 views

Why does everything written on a page appear in concentric circles when we rotate that page? [closed]

When i put a pencil in the middle of a paper and rotate it very fast, whatsoever is written on it, will appear in concentric circles. What is the reason behind this phenomenon and what is it called?
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1answer
561 views

Tough mudder “Electroshock therapy” obstacle [closed]

The Tough mudder is an obstacle race where some obstacles test someone's mental grit. One of the obstacles is the "Electroshock therapy" where someone has to run through dangling wires that carry ...
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1answer
634 views

How big would an object look at a certain distance?

I've tried looking this up and found that objects only appear smaller because of the curvature of the eye. For example: the flowers are the same size, but since the second flower is farther, angle $...
6
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1answer
11k views

Why do we see brown light?

While researching about lasers (it's my hobby), it suddenly hit me: there are lasers for every color of the visible spectrum, but there are no brown lasers. Brown isn't even on the rainbow. How is it ...
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3answers
4k views

Why do sea waves seem to be standing still when you look from the window of an airplane?

Looking from the window of a passenger plane even at moderate altitude such that one can still recognize individual waves and even something like white foam, and small boats close to the cost line, it ...
2
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2answers
754 views

Why are we not able to visualize Dimensions beyond 3 (or maximum 4 including time)?

We consciously know and feel the first three dimensions and with some thinking time as well. But according to literature like String theory etc., we have many many more dimensions. We can readily ...
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6answers
39k views

Why do objects appear smaller when farther away?

Why does the apparent size of an object change when it is farther away from me compared to when it is closer to me? Can someone perhaps explain this through an optics perspective?
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2answers
984 views

Why do we (3 dimensional creatures) see in 2 spatial dimensions? [closed]

Why do us humans, as 3-dimensional (in terms of space) creatures, see everything in 2 dimensions? Is it because the surface of every 3-dimensional object is 2 dimensional? Or because light enters our ...
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4answers
385 views

Is the hard problem of consciousness an obstacle to finding a physical theory of everything? Why or why not?

I do not understand how, without understanding the mind and how (physical) neural interactions within the brain give rise to consciousness, one can have a definitive theory of everything. There will ...
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2answers
2k views

The difference in how temperature feels inside in the summer vs. in the winter?

72 degrees feels cooler when it's hotter outside, say 90 F but warmer if it's really cold outside, say 32F However it also feels different if it's 90 vs say 70F outside. Why is that?
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4answers
2k views

Is purple in visible light?

This isn’t a duplicate. I read those pages, but those didn’t answer my questions. Please watch this. Does visible light consist of red, orange, yellow, green, cyan and blue? No purple? My definition ...
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4answers
8k views

Why does the human body feel loud music?

I was sitting close to a speaker and I could feel the sound coming from it all over my body, especially in my heart, and it pounded with the loud beats of the music. Was my heart pounding because of ...
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3answers
1k views

When does the wagon-wheel effect occur?

Sometimes you see a video of a fan or a propeller spinning very fast, and the apparent rotation is distorted. The fan can appear to be moving in the opposite direction of rotation, or even stationary. ...
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5answers
303 views

About the perception of the flowing of time

The user John Rennie suggested I ask the following as a new question: If time is continuous why would the perception of time being continuous or flowing be an illusion?
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0answers
3k views

Is there such a thing as purple light? [duplicate]

This is a question as much about color perception as the physics of light. Since I have normal vision, without color blindness, I will draw on my experiences in formulating my question. I will add ...
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1answer
153 views

If we could not see, would we think that nothing can go faster than sound?

And if so, then why does everybody keep asserting nothing can go faster than light speed (I'm implicitly assuming there could be something which we do not observe, which goes faster than light)?
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3answers
311 views

The atom, solid or liquid? [closed]

Now I know what you may be thinking, "buddy, do you realize that the quality of solid or liquid is Made by the sum total of atoms in a thing therefore an atom can't be a solid or liquid??" This, good ...
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1answer
178 views

How can monitors display a sharp image, if light travels in all direction?

The question title might be a misnomer, help me improve it. My question is, from my understanding, a light travels in all direction from it's origin point. Also I assume that in the example of a ...
3
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1answer
666 views

Do we see objects as they really are or does our brain manipulates itself?

The apparent size of an object decreases with increase in distance that's why we see rails get closer as they get farther. We don't see the rails parallel throughout their length but converging. But ...
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2answers
95 views

Time, distance perception [duplicate]

If photons going c have no local time or distance 'perception' why isn't the same true for us as we're going c relative to them?
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2answers
4k views

Why does the sky suddenly look gray through this window?

I am looking to the windowed roof of my building, and I notice that the sky, which has few white clouds, sometimes looks completely gray, as if there was a huge cover of gray clouds, but there are not....
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2answers
1k views

How powerful would an explosion have to be for its effects to be felt worldwide?

If an explosion were to occur at any point on earth, how powerful would that explosion have to be for it to be audible or otherwise detectable by every person on the planet? Detection could mean ...
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4answers
370 views

Does Free Will Theorem imply that quantum mechanics plays crucial role in our brain’s functioning (consciousness)?

Does Free Will Theorem imply that quantum mechanics plays crucial role in our brain’s functioning (consciousness)? Is opposite statement of Free Will Theorem right: If elementary particles have a ...
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1answer
1k views

From where does the sound come from when two charged objects meet in real life?

I am sure all of us have played with rubbing things and producing static electricity and when I was charging my comb by rubbing it on my hair and watching it attracting a small piece of paper, I heard ...
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1answer
3k views

Why do objects of a given color appear white under light of that color?

Under light from the sun, a red object will scatter the red component of light, and absorb all others. Hence, the human eye perceives it as "red". White objects scatter all wavelengths of light. ...
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5answers
4k views

Why do we remember the past but not the future?

The question is sometimes referred to as the "psychological arrow of time" (Hawking, 1985). Here the past is understood as a moment or time when the entropy of the universe was lower, and contrarily ...
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1answer
218 views

Why and how the Universe has (at least) 3 spatial dimensions [closed]

We are conscious to live in a 3 dimension universe. Maybe it has more than 3 spatial dimensions (like the 10 mentioned in the string/M-theory) but that is not my concern here. My question is the ...
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3answers
207 views

Am I accelerating in the fourth dimension (time)? [closed]

I have an intuitive feeling that I am accelerating in the fourth dimension. As we get older, we all perceive time moving faster. Are there any arguments or theories in physics which address this ...
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3answers
639 views

Why can colors be mixed? [duplicate]

We can combine colored light, creating other colors, at least in terms of visual perception. But how it the result physically "a different color" - if it is at all? Or is all this not a physical ...
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2answers
2k views

About our voice transferred into electrical signal

I know when we speak to the microphone, the pitch of our voice cause the vibration of magnet in the microphone, thus causing generation of different voltages of electrical signal. But my question is: ...
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3answers
947 views

Velocity measurement in relativistic perspectives

I understand the precepts of relativistic time dilation, but I'm looking to nail down the local perception of velocity in each frame. My question is threefold: Given two observers $A$ (rest frame) ...
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1answer
1k views

Will a sound composed of the frequencies 450Hz, 650Hz 850Hz have a clearly defined musical pitch? Why?

According to my lecturer, the perceived pitch of a sound composed of the following harmonics: 750Hz, 1000Hz, 1250Hz is equal to the fundamental frequency which is the highest common factor of the ...
1
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1answer
90 views

Explanation request for flashes of light [closed]

I have observed what I believe to be the same phenomenon on two occasions and wanted to ask for possible explanations. Both times, I saw flashes of whitish light, near the ceiling of a room. They ...
3
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2answers
214 views

Can we see refraction of light in the air with our eyes?

Can we see refraction of light in the air with our eyes? I am asking that because every night I see that the light in the street moving little is that because of change in the air? I do not mean ...
3
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1answer
299 views

How can one learn to visualize 4 dimensional spacetime?

I was watching Professor Leonard Susskind's lecture on Quantum Entanglements and he said that there are physicists and people who study physics, who 'rewire' themselves so they can visualize 4 ...
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2answers
446 views

Why does the colour wheel wrap around?

Red colour bares 430-480THz and Violet bares 670-750THz according to Wikipedia. What frequencies are the colours between red and violet? Will they be higher than red? or lower than violet? What ...
6
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3answers
635 views

Why does the point of intersection of two shadows look brighter?

When I sit in my garden during the day I always keep looking at the two intersecting shadows of two rods. It looks something like this: What I find weird about it is that at the point of ...
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1answer
70 views

Predicting the direction of sound incorrectly? [closed]

When i was sitting outside my house yesterday, I heard a strange sharp sound. I could not point out it's exact direction but apparently looked like coming from left but later my friend told me that an ...