I wonder about this.   If you pour water in a closed tank, it makes a noise. I have noticed that as the container becomes more and more full, the pitch of this noise also increases. Why is that?  I do not study, nor have any knowledge of beyond basic concepts, of the physics involved in sound and vibrations. However, my hypothesis is that this happens because the "chamber" where the sound is produced gets progressively smaller, therefore it behaves like a flute - as you change the shape of the chamber, the sound that air makes as it passes also changes.
120912
Have you ever noticed that when you are filling a container with fluid. As it approaches the top, it makes a different sound? You can tell by listening when your about to reach the top. Why is this?
54927
If I have a container that is full of water and I attempt to freeze the water by freezing the container, what would happen if the container is strong enough to prevent the water expansion? Could the water be in liquid state even though it is at or below freezing point?  This is probably a daft question but its something that's been bugging me.
59234
Suppose I have a wooden block that floats in water and I put it in an empty  glass beaker. Then I poured water in the beaker so carefully that no water goes under the block. In that case, would the block float or it will remain under the water?  As there is no water under the block there is no upward thrust on the base. Therefore it seems that the block would not float.  On contrary, there is tangential upward thrust on the sides of the block. Because of this thrust the block will float.   Which is the correct answer?  EDIT  I think the right answer is : the block would not float. Thanks to sammygerbil, anna v, Kieran Moynihan.  This reminds me another question.  A wooden block is floating on water in a air tight container. Is it going to float more or float less in the following cases?   All the air has been pulled out from the container. We compress the air above the water.   My Thought  Case 1:  When all the air has been pulled out from the container there is no buoyant force due to air, so total downward force acting on the block would increase and the block would float less.  OR,  As there is no air below the block no buyout force due to air. When all the air has been pulled out from the container there is no air pressure, so the block would float more.   Case 2:  When we compress the air, the density of air would increase. So the weight of the displaced air as well as the buoyant force due to air would also increase and the block would float more.  OR,  As there is no air below the block no buyout force due to air. When we compress the air, so the block would float less as air puts more downward pressure on the block.   Now which is correct or incorrect and why?
105532
I'm trying to visualize how sound waves work and I was curious about something.   So sound moves in longitudinal waves, which I think I understand.  There is a really good  explaining this.  In the video the air particles are depicted as moving from left to right (longitudinally). But do they ever move up and down even a little bit? Are they on some kind of fixed axis where they can only move longitudinally and never move even the slightest bit in a vertical direction?
77495
The Situation:  A ball is placed in a beaker filled with water and floats. It is also attached to the bottom of the beaker via a string.   The Question:  The ball is attached to the beaker, thus making the ball and beaker (and string included) a system. However, it is floating. Does the ball add to the weight of the beaker?
84696
There is a  being thrown out of a flask, literally hovering out of the container  My question is how detailed a physical explanation of this phenomenon we have?  Question: More precisely, if we used the best available mechanical physics simulator software, and we tried to simulate this behavior, would the software be able to reproduce the effect or not? My guess is not but I would like to know why not.  Or do we have to content ourselves only with handwaved explanations? I am from the school of thought that you don't understand physics until you have a reasonable certainty that you can reproduce the physics in a computer.
13745
Water in my electric kettle makes the most noise sixty to ninety seconds before the water comes to a full boil. I have been fooled many times by the noisy kettle, only to discover that the water was not yet hot enough for tea. The kettle is only at a full boil after the noise has subsided.    I have noticed the same phenomenon with many other kettles, including conventional kettles on kitchen ranges; it is not a peculiarity of this electric kettle.  Why does the boiling become quieter as the water reaches full boil?
84607
Is there any reason for why a small speaker cone cannot produce low end sound at a comparable volume to higher frequencies?  I can understand how a larger speaker would be in contact with more air and so would produce a louder sound, but why specifically is this important for the low end?  As an aside, I think this phenomenon can also be seen elsewhere, such as the size increase of the violin family (violin: small/high pitched, double bass: enormous/low pitched). If you tuned the strings of a violin to double bass pitch I doubt you’d hear much!
55195
I was reading a textbook. I found that it was mentioned the speed of sound increases with increase in temperature. But sound is a mechanical wave, and it travels faster when molecules are closer.   But an increase in temperature will draw molecules away from each other, and then accordingly the speed of sound should be slower. How is it possible that the speed of sound increases if temperature increases? What is the relation of speed of sound and temperature?
103899
When steaming milk (for a latte or other coffee drink), it sometimes produces a loud, high-pitched "screaming" sound.  I think you can usually prevent it by keeping the tip of the steaming wand on the surface of the milk longer before putting it in deeper, but that's just a guess more than anything I've actually been taught.  I've always assumed this noise means the milk is scalding, but I'm really sure.  What causes the screaming noise, and what is the best way to avoid it?
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I'm sure you have tried sometime to make a sound by blowing in an empty bottle. Of course, the tone/frequency of the sound modifies if the bottle changes its shape, volume, etc.   I am interested in understanding how the tone/frequency of this sound can be (approximately) calculated from the shape of the bottle. Is there some formula?  If you have any references about this please post them in your answers.  Being a mathematician I keep hearing that the principal tone is given by the first eigenvalue of the Laplace operator, and I'd like to understand the physical explanation.
26914
Suppose you put wheels under a compressed air tank    so that it can move horizontally to the right and to the left. Suppose there is a nozzle on the right hand side of the tank (in the picture on the backside, if you like).  If the tank is filled with high pressured air and you open the nozzle, the tank will move to the left. This is how rockets work and one can easily imagine that.   What happens when the tank is filled with a vacuum and you open the nozzle?  My first impression was, that the tank is moving to the right but someone told me, that it would be stand still. Is this true? What is an intuitive explanation for that?
37016
In this video, a device is introduced from 1 minute to 18 seconds. After entering the air, the disc at the bottom of the device will be suspended in the air. The video explains that this is because of the Bernoulli effect, but I think this explanation is incorrect, because the disc gap, the radial volume is increasing. Therefore, the reason why the disk is suspended is that the air volume becomes larger, so the pressure decreases (according to Boyle's law). If the air moves along the radial direction at a constant speed, the volume of the air must be constantly increasing, right? So the pressure is decreasing, right?
110534
We've all been there: you drop your bottle of soda at some point and when you try to open it, it bursts into foam. My question is, then: why does shaking a carbonated drink make the dissolved gas escape?
117040
So this Youtube video has been around for a while now  . Also this  may be related.  I just wanted to know if there is any standard hydrodynamic terms to explain it. Derek clearly states it is not about Bernoulli principle, as in this case the ball rotation is important.  Has any recent paper/videos discussed what happens if you do the same experiment with hydrophobic spheres? Can it be predicted with laminar flow theories or does it need turbulence?  Too many questions have been posed, but not so many responses on the internet yet.  Edit: I said Derek stated "it wasn't Coandă effect", yet what he says is that it is not "just Bernoulli's principle". Coandă effect is the typical hairdryer ping-pong ball levitation which is explained by Bernoulli's principle.   Edit2: rephrasing.  Additional comment: There seems to be two explanations "water adhere to the sphere and is ejected conserving horizontal momentum" and "Magnus effect" (ME). The later is not so obvious to me as the system is in equilibrium and there are two fluids, water and air, (does ME means air pushes the ball horizontally?).   Edit3: DESCRIPTION To avoid rot links and people that do not want to see the video, I'll try to explain the phenomena. You have a sphere and a water jet. The water jet is vertical (opposite to gravity), and touches the sphere almost tangentially. The ball not only rotates due to the water jet but also stays at constant height from the ground. The angular velocity can be defined in the direction of the cross product between the position of the contact point between the jet and the sphere (origin in the center of the sphere) and the direction of the jet. Some water drops fly away at the top of the sphere away from the jet.  Edit4: New question, would this phenomenon occur if there was no air?
112247
Both thermal energy and air are propagated through vibration of particles so why sound does not heat up the air e.g loud musical instrument  does not generate much heat ?
85821
If the shield doesn't vibrate, how could it produce sound? This would necessitate something vibrating to move the air.  The only thing that I can think of that is plausible, is that vibranium is able to quickly dampen vibrations, and isn't just immune to them. This would then allow it to produce sounds.