What concept in physics makes bubbles round?
86129
Several, actually. First, surface tension of the soap holds it together. With equal pressure inside, all surface points are equally stressed outward. And the sphere is the smallest surface area available to a certain volume. Same applies to raindrops.
524282
There are two possible reasons:\n1. A non-round object has higher surface area than a round object for same volume. This in turn could lead to higher reaction rates in portions that are not round (projections etc), finally leading to the element appearing round.\n2. The surface tension of water and buoyancy keep the element on the surface at the cost of local depression in the surface of water. Surface tension tends to make the depression round, which could make the element appear round.
432927
THANK U GOD! finally a real question!\n\nThe tiny bubbles that form when water is heated to near boiling almost always consist of dissolved air leaving the water.
478525
Everyone says that The surface tension causes the bubble to be spherical. But how? and Why? \n\nLets explain surface tension first- \nIn an air-water interface, the molecules that are close to the surface are attracted by fewer molecules of the liquid than the ones that are NOT close to the surface. The former thus, has less attractive potential energy than the latter, right?\n\nNow, for any matter (solid or liquid), attractive potential energy results in stability & repulsive energy results in instablity (common sense). \n\nSo, it is energetically unfavourable to have a surface for a liquid (or solid) as it results in loss of attractive potential energy.\n\nNow, for that reason, a bubble wants to have the lowest possible surface area to remain stable. Now, using some high level mathematics, someone found out that a sphere has the lowest possible surface area for a given volume. (it is better than a cube atleast).\n\nHence why we can see that the water bubbles and drops tend to be spherical. Due to the effect of gravity, although the drops appear oval in shape but, in the absense of gravity, all the liguid-air surfaces tend to be spherical.\n\nI hope it helped.\nHave a nice day!
302598
An interesting question. The question that may comes to \neveryone's mind is "IS the earth round?"  \nAnd the answer is no, at least \nnot perfectly round.  But it is round compared to your average cube, that is \nfor sure!  Now, my understanding of how solar systems form is pretty \ninadequate; all I can tell you is what I see on "Nova."  But basically, I \nguess it has to do with gravity, which is a CENTRAL FORCE.  What that means is \nthat gravity pulls things together along a straight line, and the more massive \none of the things is, the stronger it pulls.  When the earth was forming, it \nwas basically a big ball of dust left over from an exploded sun (a supernova).  \nGravity caused a lot of the matter to condense into a big fiery ball (our \nsun), but some of the dust was far enough away from the Sun so that the \nstronger forces were between planetary dust particles and not the sun.  SO, \nthey swirled together into a ball.  You can see something similar when you \nmake a painting with one of those "spin-art" machines; you put a card on the \nspinner, which whirls around real fast, and then you squirt paint on the card.  \nThe whirling causes the paint to go out away from the center (this is like the \nexplosion of the supernova) and droplets go out along an interesting path \nuntil they stop, which happens when the spinning force is equal and opposite \nto the force which attaches paint to the card (this is like gravity).  Now, if \nthe force attaching paint to the card were not so strong,eventually the drops \nwould get bigger - "planets."
1143659
If you are talking about the shape that you always see in cartoons, round at the bottom and coming to a point at the top, then it doesn't.\n\nThe raindrop shape is an invention of artists or whoever.  High speed photography shows that raindrops take the shape of flattened spheres due to air resistance.\n\nYou can read about it here: http://www.islandnet.com/~see/weather/history/lenard.htm
164977
If you take seven pennies and lay them out flat, then bunch them up, you will see that with one penny at the center, exactly six pennies will fit around it.  In the case of bubbles, if you have several bubbles of the same size, they will natural fall into a position that allows them to fit most tightly together.  Bubbles on top layers will either pop or fall into gaps, and this will continue until the tightest packing is acheived.  For round bubbles, this will be the sort I described.  Put a whole bunch of pennies flat on the counter, and pack them as near together as possible without over-lapping--you'll eventually find that every penny (except those on the edge) is touching six other pennies.\n\nNow with bubbles, the sides of each bubble will merge with that of those it touches in order to reduce surface tension (a thermodynamically unfavorable association between different phases, like water and air in this case).  That merging means that while each bubble will be touching six others, the sides will all be flat.  Now each of your bubbles represents a packed hexagonal structure.
462517
If there are bubbles of air then you will have less liquid than you are intending to have. Assuming you are calculating density via measurementof mass then the mass you get will be less than it should be for that volume of that liquid. As a result the calculated density will work out lower than it should do.
1060039
so that they roll. why are wheels round?
769720
bubbles are gas.\n\nthey may be surrounded by liquid or solid, but the bubble itself is there because there is gas there.
1089145
No, planets and stars are round because of gravity (to be more accurate, gravity is the curvature of space-time). This is a caused by a different phenomena than surface tension, which is due to the electromagnetic attraction between water molecules. The force of gravity and the electromagetic force are two different forces.  \n\nSurface tension does not actually make the drop round; air pressure does that.  Surface tension simply gives the drop an outer wall like the wall of a balloon.  \n\nThe reason that water drops form into spheres is the need to equalize the pressure inside the drop. Air pressure tries to squeeze the drop, and the internal pressure inside the drop pushes back  - creating the internal pressure of the drop. This puts tension on the wall of the drop (Where the wall of the drop is caused by surface tension.). The geometric shape of the sphere minimizes the wall tension (http://hyperphysics.phy-astr.gsu.edu/Hbase/surten2.html).  A shape with corners, such as a cube, would allow forces to be concentrated at the corner, which would smash the corner flat, or else cause the area around the corner to expand. A sphere allows for an even pressure distribution.\n\nThe pressure on a planet is caused by its own weight pulling its own matter inward.  A sphere allows for an even distribution of gravational 'pressure'.  \n\nIn other words, a sphere resists being crushed better than any other shape, so objects under internal or external pressure tend to become round (irregardless of what is causing the pressure).
223530
How about the adding of Gravitational Potential Energy (GPE) and Kinetic Energy (KE) as an object falls in the air to demonstrate the preservation of energy?\n\nBefore it falls all energy is GPE, as it falls GPE is converted to KE until just before it hits the floor then it is all KE.
308048
There are two theories.\n\n1.  Mass has the attribute of warping space much as a billiard ball placed on a thin sheet of rubber would warp the flat sheet.\n\n2.  Massless particles called gravitons interact between the masses involved.
527058
The "foamy" spacetime would look like a complex turbulent storm-tossed sea. Some physicists theorize the formation of wormholes therein; speculation arising from this includes the possibility of hyperspatial links to other universes.\n\nQuantum foam is theorized to create masses of virtual particles. These virtual particles make their existence known by the Casimir effect. The Casimir effect is a physical force exerted between separate objects.\n\nDutch physicist Hendrik B. G. Casimir first proposed the existence of the force, and he formulated an experiment to detect it in 1948 while participating in research at Philips Research Labs. The classic form of his experiment used a pair of uncharged parallel metal plates in a vacuum, and successfully demonstrated the force to within 15% of the value he had predicted according to his theory.\n\nSome physicists theorize that having two sets of these charged metal plates will create/connect a worm  hole between them.\n\nIf you want to take it a step further. Have a pair of plates on earth and another on a space craft moving close to the speed of light. Jumping in between the plates entering/the worm hole will allow you to travel backwards in time!
325192
Bubbles are good examples of minimal surfaces. Meaning that they will always attain a shape which gives them the smallest surface area, given the contraints upon them. No contraints (just floatin' free) will always create spherical bubbles for this reason. If you make bubbles stick to some sort of shape, or stick bubbles together, they will create more complex shapes, including some with flat sides (imagine, for instance, two bubbles stuck together, they intersect in a flat circle). So, with the right bubbles and a lot of luck, you would be able to create some rather interesting shapes in the middle of a cluster. But free-floating non-spherical bubbles are an impossibility.
874438
Any moving mass ripples spacetime.\nhttp://archive.ncsa.uiuc.edu/Cyberia/NumRel/GravWaves.html
1137727
I like the joke!  To play along, I define:\nr = metric r  and \nd = metric d\n\nV = (pi/3)*(d^2)*(3r - d)\n\nThis will work for the tank being any fraction of a sphere, not just 1/2