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While individual fire ants are hydrophobic and flounder at the waters surface, large groups of ants can link together to form a temporary living clump, known as raft, and float along the waterline for as many as 12 days until reaching dry land. [14]
In On Floating Bodies, Archimedes suggested that (c. 246 BC): Any object, totally or partially immersed in a fluid or liquid, is buoyed up by a force equal to the weight of the fluid displaced by the object. Archimedes' principle allows the buoyancy of any floating object partially or fully immersed in a fluid to be calculated.
This effect is due to the fact that molecules of the liquid are more strongly attracted to each other than they are to the air above the liquid. As such, non-wetting objects on the surface of the liquid will experience an upward force due to surface tension. If the upward force is sufficient to balance the force of gravity on the object, it ...
A floating object is stable if it tends to restore itself to an equilibrium position after a small displacement. For example, floating objects will generally have vertical stability, as if the object is pushed down slightly, this will create a greater buoyancy force, which, unbalanced by the weight force, will push the object back up.
The purpose of On Floating Bodies I-II was to determine the positions that various solids will assume when floating in a fluid, according to their form and the variation in their specific gravities. The work is known for containing the first statement of what is now known as Archimedes' principle .
There are two books of On Floating Bodies. In the first book, Archimedes spells out the law of equilibrium of fluids and proves that water will adopt a spherical form around a center of gravity. This may have been an attempt at explaining the theory of contemporary Greek astronomers such as Eratosthenes that the Earth is round.
In aerodynamic levitation, the levitation is achieved by floating the object on a stream of gas, either produced by the object or acting on the object. For example, a ping pong ball can be levitated with the stream of air from a vacuum cleaner set on "blow" - exploiting the Coandă effect which keeps it stable in the airstream. With enough ...
Note that the object is floating because the upward force of buoyancy is equal to the downward force of gravity. The fundamental principles of hydrostatics and dynamics were given by Archimedes in his work On Floating Bodies (Ancient Greek: Περὶ τῶν ὀχουμένων), around 250 BC.