Why does sound travel faster through a less dense gas, but also faster through water than air?
137886
Sound travels faster through water because the particles in water are already touching each other (in gases the particles are all spread out). [the other answers have dealt with this in more detail]\n\nHelium is less dense than air becuase helium molecules weigh less than regular air molecules (a molecule of helium is two helium atoms, so its atomic weight is 2x 2 = 4. Air is mostly nitrogen, with molecular weight 2x 14 = 28).\n\nHowever, the molecules in helium are almost exactly as close together as the molcules in air. In fact, in any gas, one mole of molecules takes up the same amount of space - 24 litres at standard temperature and atmospheric pressure.\n\nSo, sound can travel faster through helium because the particles are the same distance apart as air, but they are lighter so it is easier to get them moving.
117333
Because of it's wave-like characteristics.\nSame thing happens to sound.  Travels faster in water than in air.  If you are underwater, and you hear a firecracker go off in the air above you, when that sound is passes to the water, the water molecules being more dense, will transmit it faster.\nNo more energy is added, nor does it pick up energy, but the medium vibrates at a faster frequency with the same amount of energy.\nThe amount of energy a wave has does not correspond to the speed at which it travels.
907929
The sound waves generated in helium gas have less momentum due to the lighter molecular weight of helium. Then when they hit the air going out to the ear, they can move those heavier nitrogen and oxygen molecules around as fast. This results in a decrease in th distance between compression waves, which then sounds like a higher pitch.
690272
You will find the formula you need just over half way down the page:\n\nhttp://en.wikipedia.org/wiki/Speed_of_sound\n\nI get speed of sound is 4 x faster in oxygen than hydrogen (1/sqrt16)
564448
well actually sound is a series of vibrations and rarefractions, so when it is passed through the air the vibration is passing through the air molecules, and depending on the thickness or thinness of the air,the sound will go a further distance, also note that how loud the sound is must be taken into account. sound is not simply "absorbed" into the air, it is just the amount of strength the rarefraction and vibration is, now when there is wind, you have to take into account that sound is like an object, it will have wind resistance, or in a way. newtons second law i believe states, every force excerted onto another will  excert force equally or more back upon that object. so it is bassically just sound dying out because the vibration has no longer the power to be carried through the air.
433818
Water provides more force than air because it is\ndenser and thus has more mass:\n\nF = ma \n\nd = m / volume
1005278
Yes, light travels faster than sound. You can tell from several \nexamples. The best would probably be that of lightning and thunder. The next \ntime during a storm, if you notice when lightning flashes across the sky and \nwhen you hear thunder, you will find that it is always the lightning that \nflashes before the thunder. This is because lightning (i.e. light) travels \nfaster than thunder (i.e. sound), and reaches you faster, so that you see the \nlightning before you hear the thunder. In fact, light is enormously faster than \nsound. Light travels at 300,000,000 metres per second (i.e. 300 million metres \nper second), while poor old sound travels only at 330 metres per second.
110300
Bernoulli's equation relates pressure to the speed of a moving fluid.  That's entirely different to what the question here is.\n\nThe reason things move from high pressure to low pressure is because such a pressure gradient is statistically unstable.  The principle is so simple it's studid.  Think of a fluid as being a bunch of tiny particles, flying around and banging into one another.  At high pressure, the particles are packed closely together, and they will hit eachother more frequently than they will at low pressure.  Every time two particles collide, they are driven away from one another.  So if a particle hits a particle and bounces toward a place of greater pressure, it will be statistically very likely to hit another particle again in a big hurry.  If it bounces to a place of lower pressure, it will be statistically less likely to hit another particle in a hurry.  If you sum up all of the collisions, the result is that movement up a pressure gradient is less stable--that is, it lasts a short time--than movement down a pressure gradient.  The effect of this is that on average, you end up with a net flux of particles in the direction down the pressure gradient.\n\nThis sounds absurd, but it ultimately makes the flow occur.  You have to realize that particles move very, very fast, and collisions happen with a frequency we can barely imagine.  So imagine you're an air molecule in a soda can that's been shaken.  There's so much pressure, that any way you go, you hit another molecule almost instantly.  Suddenly the top is opened.  Those molecule that are closest to the opnening are at an extreme point in the pressure gradient: below them are crowded molecules, and above them are the more rarified atmospheric air molecules.  They bump about at random.  But if they're bumped down into the can, they go little distance before being bounced back.  If they're bumped up, they go much further before hitting another molecule.  This means that in the vacinity of the opening, the pressure is reduced, and there are less molecules in that area.  Now the pressure gradient has propagated into the can.  Those areas adjacent to that area near the opnening now experience the same effect--being bumped away from the openeing meets it with a quick collision, while being bumped toward the opening makes it able to travel further before hitting another molecule, because so many have left the can that the area near the opening is much less crowded.  This keeps happeneing until the pressure inside and outside the can is the same, due to a net flux of molecules out of the can, and it happens really, really fast.\n\n\nConservation of momentum also makes it so that in an elastic collision, the net momentum of the collision before and after a collision is unchanged.  So for fluid in a pipe, that means most collisions will keep everything going down the pressure gradient.
308060
Molecules are closer together in liquids and solids than in gas. Soundwaves are motions of molecules that basically push off each other. In a dense liquid one molecule only has to move a tiny distance before it hits another molecule and so forth, whereas in a gas it takes a while before one molecule encounters another one along its path.
181822
Sound travels in a wave.  Actually travels best through a solid.
555321
I think they've misunderstood.its not speed you are asking about? Depends on the density of the air. light wont travel as far in foggy or smokey conditions as it will under clear conditions.water and air are basically the same thing, different density. That's why it is dark at the bottom of the ocean. It is too dense to penetrate Under clear conditions the distance light will travel if indefinite as far as we know as long as there is nothing interfering or blocking the source
871688
Sound travels faster than light. Many people believe the opposite is true, citing as evidence the fact that there is a delay between when you see something far away and when you hear the sound it produces (fireworks, someone hitting a baseball, etc.). Though the sound reaches your ears before the light reaches your eyes, it takes your brain longer to process aural input, while it can process visual input almost instantaneously.
386222
sound is particles vibrating in succesion. waves. \nthere are more particles in iron so the sound is trasnfered faster.
975645
the particles of water are far more closely packed than the particles of air. air is mostly empty space and therefore with fewer particles colliding with your hand, its going to be much easier to move your hand through the air than water.
887565
Sound travels at different speeds depending on what it is traveling through. Of the three mediums (gas, liquid, and solid) sound waves travel the slowest through gases, faster through liquids, and fastest through solids. Temperature also affects the speed of sound. \nGases: \n\nThe speed of sound depends upon the properties of the medium it is passing through. When we look at the properties of a gas, we see that only when molecules collide with each other can the condensations and rarefactions of a sound wave move about. So, it makes sense that the speed of sound has the same order of magnitude as the average molecular speed between collisions. In a gas, it is particularly important to know the temperature. This is because at lower temperatures, molecules collide more often, giving the sound wave more chances to move around rapidly. At freezing (0º Celcius), sound travels through air at 331 meters per second (about 740 mph). But, at 20ºC, room temperature, sound travels at 343 meters per second (767 mph). \n\nLiquids: \n\nSound travels faster in liquids than in gases because molecules are more tightly packed. In fresh water, sound waves travel at 1,482 meters per second (about 3,315 mph). That's well over 4 times faster than in air! Several ocean-dwelling animals rely upon sound waves to communicate with other animals and to locate food and obstacles. The reason that they are able to effectively use this method of communication over long distances is that sound travels so much faster in water.\n\nSolids: \n\nSound travels fastest through solids. This is because molecules in a solid medium are much closer together than those in a liquid or gas, allowing sound waves to travel more quickly through it. In fact, sound waves travel over 17 times faster through steel than through air. The exact speed of sound in steel is 5,960 meters per second (13,332 mph)! But, this is only for the majority of solids. The speed of sound in all solids are not faster than in all liquids
8835
less dense... it is common sense the density of substances go from solid liquid to gas (most dense to least) neon is a gas thus it would be less dense than water which is a liquid
255915
Yes, speed of sound is "fixed", like the speed of light and does not depend on the frequency\n\nFrequency affects the volume, if it's peak and trough changes. Higher the peak and trough, the louder the sound and vice versa.\n\nFrequency affects the pitch,if it gets higher or lower. Higher the frequency, higher the pitch, lower the frequency lower the pitch.\n\nHowever sound does change speed depending on the medium it's traveling in.  It travels faster in water,I believe.\nAnd it cannot travel in vacum, so it has zero speed in space.