Buoyancy. Buoyancy is the tendency of an object to float in a fluid, such as air or water. The principle of buoyancy was first discovered by Greek mathematician Archimedes (c. 287 â 212 b.c.) and is therefore often called Archimedes' Principle.therwise, it floats. The formal statement of Archimedes' Principle is this: the buoyant force acting on an object placed in a fluid is equal to the weight of the fluid displaced by the object. Suppose that the wood block in the example above has a volume of 1 cubic foot. A cubic foot of water weighs about 62.4 pounds.
Epidemic: The occurrence of more cases of a disease than would be expected in a community or region during a given time period.A sudden severe outbreak of a disease such as SARS. From the Greek epi-, upon + demos, people or population = epidemos = upon the population.. See also: Endemic; Pandemic.pidemic: The occurrence of more cases of a disease than would be expected in a community or region during a given time period.
The definition of an epidemic, as used by those who study the phenomenon, is more cases of an illness than one would normally expect to see, based on The definition of an epidemic, as used by those who study the phenomenon, is more cases of an illness than one would normally expect to see, based on previous experience. In many cases the word epidemic describes a disease that creates a threat to the general public and that kills many people. So according to the first definition, two cases of smallpox constitute an epidemic, since there is currently no smallpox in the world. On the other hand, 75 cases of yellow fever would be an epidemic if we only expect to see 20 cases.