Buoyancy

Examples of Buoyancy in the following topics:

• Complete Submersion

  • The buoyancy force on a completely submerged object of volume is $F_B = V \rho g$ .
  • In general, the buoyancy force on a completely submerged object is given by the formula:
  • The buoyancy force on the cylinder is equal to the weight of the displaced fluid.
  • The buoyancy force on an airship is due to the air in which it is immersed.
  • Identify factors determining the buoyancy force on a completely submerged object

• Gas Vesicles

  • Gas vesicles are spindle-shaped structures that provide buoyancy to cells by decreasing their overall cell density.
  • Gas vesicles are spindle-shaped structures found in some planktonic bacteria that provides buoyancy to these cells by decreasing their overall cell density .
  • Positive buoyancy is needed to keep the cells in the upper reaches of the water column, so that they can continue to perform photosynthesis.
  • They provide more buoyancy per unit of protein than narrow gas vesicles.

• Buoyancy and Archimedes' Principle

  • The reasoning behind the Archimedes principle is that the buoyancy force on an object depends on the pressure exerted by the fluid on its submerged surface.
  • The buoyancy force on this amount of fluid must be the same as on the original object (the ship).
  • However, we also know that the buoyancy force on the fluid must be equal to its weight, as the fluid does not sink in itself.
  • Therefore, the buoyancy force on the original object is equal to the weight of the "displaced fluid" (in this case, the water inside the dashed region (b)).

• Flotation

  • An object floats if the buoyancy force exerted on it by the fluid balances its weight.
  • An object will float if the buoyancy force exerted on it by the fluid balances its weight, i.e. if $F_B = mg$.
  • Express the relationship between the buoyancy force and the weight for a floating object

• Cerebrospinal Fluid and Its Circulation

  • Buoyancy: The actual mass of the human brain is about 1400 grams; however, the net weight of the brain suspended in the CSF is equivalent to a mass of 25 grams.
  • The brain therefore exists in neutral buoyancy, which allows the brain to maintain its density without being impaired by its own weight.

• Weight

  • In this case, the weight of the object varies due to the force of buoyancy.

• Vesicles and Vacuoles

  • Vesicles are involved in metabolism, transport, buoyancy control, and enzyme storage.

• Static Equilibrium

  • This force which counteracts the weight of a region or object within a static fluid is called the buoyant force (or buoyancy).

• Plant Adaptations to Life on Land

  • Water also provides buoyancy to organisms.

• Geomagnetism

  • The motion of the molten outer iron core is sustained by convection, or motion driven by buoyancy.