why do bubbles float up?
84665
Air bubbles float up in water due to buoyancy because they displace the weight of water equal to their volume.  Water pressure is greated at greater depths therefore there is slightly more hydraulic pressure upwards on the bottom of the bubble than downwards on the top and the bubble is pushed upwards.  As the air bubble rises the pressure is reduced allowing the bubble to grow and it increases in volume and buoyancy as it travels to the surface.  This effect can also release and grow excess nitrogen in the blood of a diver causing growing nitrogen bubbles that cause great pain or even death and is called the bends (occurring especially in large joints that bend).\n\nOf course, soap bubbles float up in air due to air currents.  In a still room they float down to the floor and pop!
159084
Ice floating is because of water's expansion upon freezing. It lowers the density below that of liquid water, meaning it floats.
8528
All freezing (or rather: crystallisation) occurs on surfaces or crystal seeds. Water freezes "from the bottom" because liquid water closer to freezing has a greater density than solid water (aka ice), so the frozen crystals float up. In cases where the solid has  a greater density than the liquid (probably the majority of cases), the solid will sink down.
494151
It's bernoulli's principle. Fluids have a lower pressure when moving than when still. Since the water is moving past the spoons (which act like the wing of a plane) they feel a pull from the pressure drop and come together. Try it with a peice of paper sometime. Roll a piec of paper up so when you place it on a flat surface it looks like a curved bridge. then blow under it and it will collapse instead of blow away. It's pretty neet.
1043479
...because their density is less than water density (1000 Kg/m^3).\n\nIf the density of an object is less than the density of the water, it floats on the surface of the water. If the density of the object is equal to the density of the water, the object floats anywhere inside the water. If the density of the object is more than the density of the water, the object sinks to the bottom.
538859
When one is swimming under water,it`s easy to view bubbles from your mouth or nose.If it`s possible for the formation of bubbles then it`s possible to blow a balloon though the outward pressure exerted by the balloon will be imence compared to the inward.You can still succeed if you use a good electric pump.
6350
If it has an air bubble then tie a string around the upper end and whirl it around over your head.  The force should make the bubble rise.
268318
Floaters are turds that have an unusually high gas content. Sometimes the gases produced by bacteria in our gut don't have a chance to collect into a large fart bubble, but remain dispersed in the feces. The poop then comes out foamy, and has a lower density than water. Poop with a high fat content will also float.
461222
its not just that "heat rises", but that things with lower densities rise above things with higher densities. ice floats in water, helium floats in air, etc.  heat is not an object that can rises, but it is an attribute of particles that affects their density. just like hot air rises, when a flame burns, it produces hot gases that rise. these gases are hot enough to produce light, so we see the light rising with the gases. by the time they have risen above the flame, they are no longer hot enough to give off light, so the flame doesn't go up forever.
567852
Both are floating because of differences in bouyance and density.\n\nThe hot air balloon floats because it is less dense than air making it bouyant. It will consequently rise into the air until the weight of the air it displaces is equal (density) is equal to that of the surrounding atmosphere, which is why balloons do not go flying off into space.\n\nA scuba diver has the same problem, but in reverse. As he goes deeper, the density of the water is increasing and pushes him or her back. Therefore, divers tend to sink to a specific depth unless they can increase their density. This is usually accomplished by bringing additional weight.
190514
Density of matter is the reason anything floats.  Any object that displaces its own weight will float. Salt water raises the density of water. Consequently any object will float easier in salt water because it only has to displace little weight compared to non salt water
439796
Oil has less density than water so it floats.  When it's empty, air has less density than water.  Same thing.  Or it has to do with the displacement as mentioned below...
64876
Buoyancy is simple.  If the weight of the liquid moved by insertion of an object into the liquid is greater than the weight of the object, it will float.  That is why the size of ships are measured in displacement.  The "Displacement" refers to the weight of water that is "moved out of the way".\n\nThink of it this way - take two identical spheres with the exact same outer material and thinkness.  One is hallow, and one is filled with lead.  Of course, we know that the one filled with lead will sink?  Why?  Because it weighs more than the water that is being moved out of the way.  How do you make it neutrally bouyant?  Simply fill it with enough lead that equals the weight of the water displaced by the sphere.\n\nThis is called Archimedes Law of Bouyancy.  Google/Yahoo search it and you should find some illustrations to help explain.
249282
Despite the air bubbles, mine seems to be pretty random.\n\nBut I'm curious, did you think that some answers are more common than others? I'll give mine a shake ask what it thinks is the most common answer...\n\nConcentrate and ask again.\n\nDamn!\n\nVery Doubtful.\n\nHmmmm...
231721
The soap bubbles are round because the surface tension of the soap tries to shrink, when the surface reaches an equal tension a sphere is formed.
29645
It probably is evaporating from the top. The bubbles on bottom are just more visible.
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!