why does a balloon rise faster in water then in air?
965619
buoyancy forces are what cause a balloon to rise whether in water or air.  buoyant forces are proportional to the density of the media being displaced.  water, having a much higher density than air, when displaced produces a greater rising force on the balloon, ergo the balloon moves faster.  air, having a higher density than helium, when displaced also produces a greater rising force on the balloon, ergo the balloon still moves but slower than in water.
135250
When you are sitting in an airplane, the air around you is traveling with you in that "bubble" which is the airplane.  Therefore, sound acts the same as it would on the ground.  Sound is carried in air (and to some degree, other materials), but not in a vacuum.  So the paradoxes which crop up about traveling faster than light do not apply to traveling faster than sound.
331738
A full baloon will weigh more if you are filling it with room air.  The air under pressure will mean there are more molecules in the balloon.  More molecules of 'x' weigh more than fewer molecules of 'x'.
412631
A balloon filled with hot air rises because of the force of buoyancy. That means the density of air inside is lesser than the surrounding air (because hot air expands thus density decreases) and thus there is an upthrust acting on the balloon. Now, if the surrounding air is at the same temperature then its density is same as that inside the balloon and so the balloon will not rise. But the balloon will not not remain at the same point. it will fall because of the weight of the rubber in it.\n    In case of exploration on other planets, firstly other planets have very low density of air in the atmosphere (most of them do not have any air) and secondly even then is one wants to use this one has to heat up the balloon to a temperature for which the density decreass lower than the surrounding. Hope this answers your question.
605564
Water doesn't slow down gravity. Gravity always pulls things down at roughly 9.8 m/s^2 (at most places on Earth, anyway). What happened, though, is that the water slowed down the desent of the coins. Remember, water is a molecule. When gravity pulled the coins down through the water the water molecules pushed back up against the coins. Its Newton's law, "for every action there is an equal and opposite reaction." Air actually works the same way. Its called terminal velocity. If you jumped out of a plane you can only fall so fast before the force of the air molecules acting against gravity equals the downward force of gravity, thereby keeping you from accelerating downward to a faster speed.\n\nNow, as for why one hit sooner then the other, that's because of how they fell. If the coin fell flatwise on the water it falls slower because there is more surface area of the coin in the way of the water. If the coin falls on its edge there is less surface area of the coin to meet the opposing force of the water and, therefore, less resistance (although the coin will flop around and turn from the force more readily). Actually, predicting a coin's free movement through a liquid is quite difficult and involves a lot of fluid dynamics and center of mass stuff.\n\nFor short distances, though, you can generally fake a rough estimate by simplifying math. You know those things with a fishbowl and a shotglass that most places like Perkin's have? Where if you drop a quarter into the glass you get a free cookie or something? Most people drop the coin edgewise and then wonder why the coin misses. The best way to do it is drop the coin in flat over the glass because the force acting against the coin is more balanced and less prone to exerting a torque the the coin as it falls. Try it sometime and see for yourself.
1003953
Well, the different between air and helium on the weight of the balloon is marginal, so you would expect little or no observable distance. \n\nBut in principle its not as simple as is being made out here. Think for a moment about what keeps a ball up and what brings it down. Its hit into the air at first, and then a combination of gravity and air resistance bring it down. \n\nIn a vacuum the trajectory would depend only on initial velocity, because kinetic energy and potential energy both depend linearly on mass (so it cancels). In air the air resistance is proportional to square of the speed and size but not mass.\n\nNow, about that kick. Does it give 1) constant energy independent of the mass of the ball, 2) constant speed to the ball independent of its mass \n\nIf 1) then the heavier ball will be slower when kicked, so will not go as far\n\nIf 2) then the distance will be the same in vacuum as above but the larger ball will have more energy and so will take longer to slow by drag - it will go further
121797
Adding air to a tank doesn’t make it float better. Air has weight. ADDING air to anything will make it heavier. The tank would float best if you could take all the air out of it altogether, but you can’t do that without it collapsing. In fact if you could take all the air out of the tank without it collapsing it would float so well that it would be possible for it to float away on the air like a helium balloon. \n\nI kid you not.\n\nSo why does adding air to a tank APPEAR to make it float better? It’s not because you add air to the tank, it is because you are forcing water out of the tank. Although air has weight it weighs much less than water. When you add more air you force out more water. That makes the tank relatively lighter and it floats better.
297952
The hotter air is, the faster the molecules are air move around, bashing into things.  That mass of moving molecules is what keeps a balloon inflated-its literally uncountable trillions of tiny molecules acting like tennis balls banging around.  Increase the heat, and those molecules go faster, and hit the surfaces harder. They also spread out more, which is why hor air is lighter than cold air...less density of molecules. You put a fire in a bottle, and the air molecules move faster, and get more dispersed.  It fills the balloon, because of this expansion of the air.  As it cools down, the molecules collapse in closer together and move more slowly, and thus the balloon collapses.
194414
Water is denser than air and transfers heat more rapidly.
807839
heat. As you heat the air inside the balloon, the thermally excited air will escape from the bottom hole. Now the balloon is filled with less air and is there fore less dense.
49373
When you put an object in water--or any other fluid that is minimally compressable, like milk or oil or alcohol--the object takes up space.  Especially for fluids that are very runny--like water, in contrast to, say, old crank-case oil--the fluid will fill every nook and cranny available.  Since the water, or other non-compressable fluid, has to move out of the way for the object put in it, the apparent rise in the total volume of water-plus-object is due to the volume of the object.\n\nOf course, if the object FLOATS in water, you're in a whole new situation: the object will displace (move aside) exactly the amount of water that weighs what the object does.  That's a whole different discussion!
726772
Its a trick Q...\n1. If floating on Surface, then 0 (since ur ballon is massless, although theoretically, nothing is massless..)\n2. If forced to stay inside water, then it would be equal to the weight of water displaced (i think ur Q is phrased wrongly, it is 1000cm3 displaced water ( or else the answer depends on the volume of the balloon).. Or simply, it is equal to the force used to keep the balloon inside water.
898627
The idea is that the increase in hydrostatic pressure of the water will cause a decrease in volume of the balloon. You are told that the temperature of the ballon is constant so that you can make the assumption PV = constant = Pa Va, where Pa Va are the pressure and volume at atmospheric conditions.\n\nThe bouyant force is simply the weight of water displaced, and therefore is it proportional to the volume of the balloon. You can assume that the water is incompressible and therefore constant density.\n\nSo, saying that the bouyant force is 1/2.4 of the surface value means that the volume has decreased to Va/2.4.\n\nPa Va = Pb Vb; Vb = Va/2.4 --> Pb = 2.4 Pa.\nRemember that this means absolute pressure.\nThe absolute hydrostatic pressure in the water is:\nPw = Pa + (rho) g h\nwhere h is the depth below the surface.\nSo: 2.4 Pa = Pa + (rho) g h\nh = (1.4 Pa)/((rho) g)\nPa = 101 000 N/m^2\nrho = 1000 kg/m^3\ng = 9.8 m/s^2\nh = 14.4 m
439452
Sure it does.  If there's no mass attached, you just need enough buoyancy to lift the balloon itself.  If you have a mass attached, you have to lift them both, so you need more buoyancy.  The more buoyancy you need, the more you have to heat the balloon.
36049
In hot water, it expands because the air molecule inside it move faster and it may pop. In cold water, it shrinks because the particles move slower. If u move it quickly from hot to cold water or vice-versa, it may pop too because of the severe change in temperature.
433818
Water provides more force than air because it is\ndenser and thus has more mass:\n\nF = ma \n\nd = m / volume
951147
The air inside a balloon is exerting pressure on the outside of the balloon. When the air escapes, that pressure is concentrated in one direction. the fast moving air near the opening strengthens pressure on the current of air, and so it pushes the balloon forward. This is also expressed in Newton's Third Law of Motion.