why are bubbles in water circular or oval in shape? why they are not any other closed shape?
401485
Well ... nature does love economy! A sphere has the smaller surface area for the same volume that any other three dimensional shape.Also, in regular conditions,  there is no pressure variance inside or around the sphere to cause deformation.
377530
The shape of a drop of rain is constrained by the surface tension, which tries to give it the shape for which the surface area is minimum. For a given volume, the spherical shape has the minimum surface area. That is why rain drops acquire spherical shape.
1171212
The spherical shape is the strongest against internal or external pressure.  Next comes a cylindrical shape with spherical end caps.  Next comes a cylindrical shape with indented end caps sort of like the bottom of  a champagne bottle.\n\nThe spherical shape also has the most volume for the surface area so less metal is needed to make the vessel.  \n\nIn other words, you get the strongest vessel using the least amount of material, with a sphere.
541336
Just an hypothesis:\n\nIn round glasses, the water ripples caused by hitting the glass travel from the wall of the glass to the center and then back, and so on. Since the shape of the ripples stays the same when going inwards or inwards (circular) the waves can amplify themselves by adding up the energy (two waves can join in a larger wave) which enhances the vibration of the walls, hence you get a long sound. \nIn a square glass, the ripples departing from opposite walls will tend to cancel each other due to their opposite directions of movement. This would dim the sound.
656895
It had been conjectured that two equal partial spheres sharing a boundary of a flat disk separate two volumes of air using a total surface area that is less than any other boundary. This equal-volume case was proved by Hass in 1995, who reduced the problem to a set of 200260 integrals which they carried out on a PC. Frank Morgan, Michael Hutchings, Manuel Ritoré, and Antonio Ros finally proved the conjecture for arbitrary double bubbles in early 2000. \n\nIn this case of two unequal partial spheres, Morgan et al. showed that the separating boundary which minimizes total surface area is a portion of a sphere which meets the outer spherical surfaces at dihedral angles of . Furthermore, the curvature of the partition is simply the difference of the curvatures of the two bubbles.\n\nProbably not any huge influence on society, however.
403281
take a straw (cylinder) and ram it through a potato.  If you do it right, the straw will go right through the potato!  The cylinder is the strongest and most stable of the shapes and you can see why soups, veggies, fruits, etc. all come in cans!\n\nRight triangels, or right angles are all around you.  The floor and the wall of you room for example.  The bottom of a pool is a good example of an obtuse triangle, suspension bridges - trapezoid, if you look at the tip of a pencil - it's a cone but the shape of a cone when you look at it head on is a scalene triangle
359367
The parabolic structure is stronger than a circular strucure or dome.\n\n---Addition---\n\nLet's think in an egg. An egg has two different shapes in each end, one is more rounded like an hemisphere and the other is more like the shape of a paraboloid.\nIf you press the egg from both ends, the egg brakes always \nfrom the more rounded one, the hemisphere looking shape instead of the paraboloid looking end.
735301
For a bubble to exist, the surface tension of the bubbles surface (interior and exterior surfaces) is in a delicate balance with the liquid sandwiched between the two surfaces. When you touch the surface of a bubble with something dry, it can, though doesn't always, disrupt the surface tension allowing a hole to form. Once a hole forms, the air, which is under a light pressure, rushes out as the surface tension seeks to reduce the surface area or the liquid forming the bubble - collapsing the bubble.
483817
Because they started as gas/liquid, and round is the lowest energy state for a liquid.\n\nLike a raindrop.
703681
Place a drop of water on horizontal glass plate gently.\n\nContrary to our expectation that the contact area should be a perfect circle, the area will have an irregular area.\n\nIf we clean the glass thoroughly and repeat the experiment we can see that the area is some what circular.\n\nThis shows that only if the glass plate is perfectly clean and has a perfectly plane, t surface (with out any surface waviness) the area of contact will be circular.\n\nThe surface tension between the glass and water makes the surface of water to be at an angle called angle of contact.\n\nIf the glass contains impurities and if the surface is not perfectly plane  then the angle of contact will not be uniform and constant and hence the area of contact is of some irregular area.\n\nIn a vertical window pane, the gravity pulls the water drop and and at each point of contact, the surface tension prevents the pull at different angle due to the variation of surface tension at each point due to impurities and surface waviness.\n\nThe water moves along the resultant force which is not uniform. \n\nThis is the reason that the water is not moving straight down.\n\nIf the water goes almost straight down we can conclude that the glass is almost clean.
884879
Because the earth is round, and if you made your flat map a oval(circle), the oceans would connect and become one!
518623
when u swirl the water, if the object floating on it is not moving at the same speed, it would have a lower outward force. They r then pull by gravity towards the lower point... the middle of the swirling water. whichever thing slows down first, it will "drop" to the middle.\n\nI notice too that even if the thing does not float, like sugar, they r concentrated at the middle in the bottom. I think that's due to gravity too. When u swirl, water goes to the side and when the roundabout motion slows, water slowly falls back down to the middle. there's a net flow toward the middle and hence dragging the sugar to the middle.
69283
There is a solution used by magicians to make bubbles that are more difficult to break than ordinary bubbles.  These bubbles can be caught and bounced in your hand if you are wearing soft cotton gloves.  This type of bubble could possibly be forced into a square shape, however it would loose it's hard angles the second it was set free.  The force of pressure inside the bubble is always going to force it to expand into a more bulbish rounded shape.  So the answer is YES you can MAKE a square bubble, but it wont stay that way.
759894
Liquids like water usually have high surface tension meaning that they tend to minimize their surface area. Now this also means that stretching such a substance  (like you do with a bubble gum) is difficult. \nWhen a substance known as surfactant (used to decrease the surface tension of water) is added, the surface tension decrease and stretching the surface is more easy. It becomes now easy for the liquid to trap a certain volume of air and stretch its flat surface to form a bubble.\n(It does not mean that plain water does'nt form bubbles at all - it does so (as you observe when you pour water from a faucet in a glass) but the bubbles quickle is finished as the high surface tension forces the surface to minimum area - the flat surface.\n\nSo it is clear that whenever you decrease the surface tension of a liquid - by adding a surfactant (detergent in common household) it enhances the bubble formation by little agitation of the liquid.
358036
The most efficient shape for an egg would be a sphere. This would need the least amount of shell to enclose a given volume, and as shell is an "expensive" thing for birds to make (in terms of energy/ food resources/ minerals). That's a good thing in evolutionary terms.\n\nThe "egg" shape is a modification of the sphere that can stop the egg from rolling away and breaking! This is most obvious in birds that nest on sea cliffs (such as gannets). Push a gannet's egg and it rolls around in a circle. That may be a reason the asymmetric shape evolved originally. This effect is less pronounced in birds that have evolved to make cup-shaped nests, as it's no longer necessary, so in some cases their eggs have lost this ability to roll in a circle even though they're still oval.
1152351
A bubble, even at the deepest levels of the ocean is still a gas.  It is lighter, or more buoyant that the liquid it is in.  At the bottom of the ocean the bubble is really compressed, and squeezed down to a tiny size.  As the bubble rises, it will get bigger, as the pressure decreases.  You can see this for yourself in a swimming pool.  Go down to the bottom and blow out  some bubbles, watch them expand as they rise to the surface.\n\nAlso the bubble is being squeezed from all sides, not just down.  That is how pressure works, all directions equally.
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.