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67
votes
8answers
7k 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 ...
16
votes
9answers
4k views

Why do objects appear smaller when viewed from a distance? [duplicate]

Yes, I know all about perspective (I'm an artist). I even have some basic knowledge of descriptive geometry. I know how it works. My question is more about why it works. I have a sneaking suspicion ...
16
votes
2answers
4k 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 ...
14
votes
9answers
648 views

How to explain (pedagogically) why there is 4 spacetime dimensions while we see only the 3 spatial dimesions?

I have been asked this question by a student, but I was able and in the same time incapable to give a good answer for this without equations, so do you have ideas how one can explain this in a simple ...
10
votes
3answers
15k views

What is the color of a mirror?

A mirror couldn't be white, as then you wouldn't be able to see your reflection so clearly. It wouldn't be transparent, as that then won't reflect. So what color is it?
10
votes
2answers
1k 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....
10
votes
3answers
2k 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 ...
7
votes
5answers
628 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. ...
6
votes
2answers
992 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.
6
votes
3answers
7k views

What happens to sound waves?

I apologize if this is a naive question, but I never really learned about this. I'm curious as to what happens to sound waves after they are "used"? For example, if I say something to you verbally, ...
6
votes
1answer
277 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 ...
5
votes
3answers
359 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 ...
5
votes
4answers
791 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 ...
5
votes
1answer
548 views

Why does the visible light spectrum appear to be circular [duplicate]

I'm not sure if this is an acceptable place to ask this question, as it may have more to do with the biological workings of human eyes than with the physical properties of light, but I'd rather hear a ...
5
votes
2answers
311 views

Is the color wheel just an optical illusion? [duplicate]

As a kid, I was taught that that blue and yellow make green, yellow and red make orange, and red and blue make purple - forming the subtractive color wheel. As an adolescent I was taught that blue and ...
5
votes
1answer
168 views

To what degree does guitar construction affects the vibration of the strings?

There's an old debate going on in the guitar community about how much does wood choice and body shape affect the sound of an electric guitar. No one denies that there's a difference acoustically (how ...
4
votes
3answers
2k views

Why we see upright images?

Since it's convex lens there in our eyes so image formed on our retina is inverted, so how come that we see upright images?
4
votes
1answer
122 views

Differences of waves in water and air

When one drops a pebble in a body of water, one can observe multiple waves emanating from the point the pebble came in contact with water. Be it because the water "jumps" up and comes back down, ...
4
votes
2answers
213 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 ...
3
votes
2answers
238 views

Distance and Speed

When I look up in the sky and I see a plane moving and it's further away why does it seem to move so slow compared if a flock of geese flies over at same time and seems to travel faster?
3
votes
6answers
2k views

Why do object appear smaller when it is further away?

This might have nothing to do with physics but why does the size of an object change when it is further away from me compared to when it is closer to me? Can someone perhaps explain this through an ...
3
votes
2answers
81 views

Why do some people support more electricity than others?

There is a game where people hold by their hands and two of them touch the electrodes of a shock box, then an electric current flows through them. I understand that since they are all making a single ...
3
votes
2answers
524 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: ...
3
votes
7answers
15k views

As 3-dimensional beings, do we really have 3-dimensional vision?

I was watching this video on YouTube of a high school student explaining perception in different dimensions, basically stuff he learned from reading the book Flatand. At one point in the video, he ...
3
votes
1answer
247 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 ...
3
votes
1answer
221 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 ...
3
votes
1answer
183 views

Why do beverages taste different based on how cold they are? [closed]

Why does temperature effect the taste of beverages? Specifically, how does the temperature for example mask certain tastes ie filtered vs unfiltered water taste very similar at colder temp and Is ...
2
votes
4answers
235 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 ...
2
votes
2answers
134 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 ...
2
votes
3answers
394 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 ...
2
votes
3answers
442 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) ...
2
votes
1answer
55 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 ...
2
votes
1answer
41 views

Why does our eyes see red when exposed to too much light? [closed]

When I looked into my projector when it was on the blue screen it left a red spot in my vision. I should not have tried it but all the colors left a red spot. Why not a blue or yellow spot was left?
2
votes
1answer
141 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 ...
2
votes
2answers
54 views

Why don't eye lenses alter depth perception?

What it is going to do is bend the rays so that light from infinity "appears" as though it is coinciding with a person's far point. In doing so, it allows the person to see a clear image, without ...
2
votes
1answer
75 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
votes
1answer
66 views

Observable universe does it account for farther away galaxies measure of the observable universe?

From our planet we can only see so far on any direction. If a galaxy farther out than ours had a planet would its view extend beyond our measurements?
2
votes
2answers
2k views

Do we see color with higher frequency first?

Out of the 7 colours of the rainbow, violet has the highest frequency and the smallest wavelength. Does this mean that our eye sees it first? If yes, then why? Does it travel at the same or higher ...
2
votes
0answers
556 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 ...
1
vote
1answer
149 views

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

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 ...
1
vote
1answer
546 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
vote
1answer
61 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?
1
vote
1answer
926 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 ...
1
vote
1answer
651 views

How can you test what color different people perceive? [closed]

If I would show someone a yellow object and ask them, "is this object yellow?" That person would say "yes". But I could never know if my perception of the color yellow is the same as that other ...
1
vote
2answers
89 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.
1
vote
2answers
55 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?
1
vote
4answers
4k views

If we had three eyes, would our visual perspective be fourth dimensional?

If one covers up one eye, then he loses depth perception (two dimensional perspective). When we uncover that eye, we can now see depth (three dimensional perspective). My question is if we had four ...
1
vote
1answer
62 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 ...
1
vote
1answer
76 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 ...
1
vote
0answers
59 views

Is there any evidence that everyone sees colours the same way? [duplicate]

We all know that the sky is blue. Grass is green. Blood is red. But, how do we know that everyone sees these colours more or less the same? How does one know that my ...