Difference Between Buoyancy and Upthrust

Main Difference – Buoyancy vs Upthrust

The two terms Buoyancy and Upthrust are frequently used in fundamental physics. Even though some people use them interchangeably, they have different and particular meanings. Buoyancy is the ability of an object to float in a fluid whereas upthrust is a force exerted on an object by a fluid within which the object is submerged. Simply, buoyancy is just a tendency of an object to rise in a given fluid when it is submerged. But upthrust is the buoyant force exerted on the object by the fluid. This is the main difference between buoyancy and upthrust.

What is Buoyancy

Buoyancy is what we perceive as the tendency of an object to rise when it is submerged in a fluid. It can be defined as the ability of an object to float in a fluid (liquids or air). Buoyancy can also be explained as the ability of a fluid to make a given object float in the fluid. However, the power of the buoyancy or the ability of an object to float depends on the density of the fluid as well as the properties of the object (density of the object, shape of the object, etc.). The denser the fluid, the greater the buoyancy effect of the fluid. The lighter the object, the greater the buoyancy effect of the object. Simply, the power of the buoyancy is determined by the density difference between the fluid and object. However, the effective density of an object can be controlled in different ways. For example, the effective density of a hollow cylinder is less than that of a solid cylinder made of the same material.

There are hundreds of applications of buoyancy effect such as hydrometers, ships and, submarines. The buoyancy effect can also be used to determine the density of solids and liquids.

Difference Between Buoyancy and Upthrust

What is Upthrust

Upthrust, also known as the buoyant force, is the force exerted by a fluid on an object. As the term suggests, upthrust always acts upwards. Therefore, upthrust always acts against the weight of an object. The buoyancy of a given object in a particular fluid is determined by the upthrust acting on the object.

If the upthrust is equal to the weight of the object, it will float in the fluid. Flotation can be seen when the effective density of the object is less than that of the liquid. But if the effective density of the object is greater than that of the liquid, the weight of the object becomes greater than the upthrust exerted by the liquid on the object. So, the object sinks in the fluid.

The magnitude of the upthrust can be determined using the Archimedes’ principle. The Archimedes’ principle states that the upthrust is precisely equal to the weight of the fluid displaced by an object.

Upthrust is useful in many applications, especially in marine engineering and cargo transport. Vessels such as ships and boats are designed in such a way that the weight of water displaced by a vessel equals the weight of the vessel when it is partially submerged in the sea. Therefore, they float in the sea according to the Archimedes’ principle. The volume of the underwater portion of the hull gradually increases with the weight of the load. In order to avoid overloading, it is very important to monitor the power of the upthrust (stability of the vessel) while loading. Normally, the hull of a vessel is marked with load lines (also known as Plimsoll lines) which help to monitor the stability of the vessel.

Unlike ordinary vessels or ships, submarines are designed to operate underwater. A submarine has a ballast tank which is used to control its depth. When water is pumped into the ballast tank, the weight of the submarine becomes greater than that of the sea water (upthrust) displaced by the submarine. So, the submarine sinks according to the Archimedes’ principle. When water is released from the ballast tanks, the weight of the submarine becomes less than that of the sea water (upthrust) displaced by the submarine. So, the submarine moves upward. Submarines can travel at a fixed depth by balancing the upthrust and its weight.Main Difference - Buoyancy vs Upthrust

Difference Between Buoyancy and Upthrust

Nature

Buoyancy: Buoyancy is an ability of a liquid or an object.

Upthrust: Upthrust is the force.

Meaning

Buoyancy: Buoyancy is the ability of an object to float in a given fluid.

Upthrust: Upthrust is the upward force exerted by a fluid on an object partially or fully immersed in the fluid.

Main Factor

Buoyancy: The density of the fluid is the main factor that affects the buoyancy.

Upthrust: The weight of the object is the main factor that affects the upthrust.Difference Between Buoyancy and Upthrust - infographic

 Image Courtesy:

“Image 1″ (Public Domain) via

“Upthrust” by Yupi666 – Own work, via

About the Author: Kuma


Related pages


different sonnetscharacteristics of realism and naturalismsanitary fittings definitionsome homographscompressible and incompressible fluid flowwhat are the different kinds of adverbswhat is the difference between exons and intronscharacteristics of inner and outer planetshow are light microscopes and electron microscopes differentstate and prove law of conservation of momentumslime layerexamples of predicate nominativeswhat is the difference between king and emperorethanoic acid ethanoldistinguish between eukaryotic and prokaryotic cellsfare vs fair definitiontonnes versus tonsinternal monologue definitiondefine common and proper nounsdifference between a silky and yorkiedefine kinetic frictiondefine honesty and integrityadjectives attributive and predicativedoes dolphin have gillswhat is the difference between essential and nonessential amino acidsis absorbance directly proportional to concentrationthe difference between atp and adpalkali earth metals on periodic tabledefinition of prologue and epiloguewhat is entropy and enthalpy in thermodynamicsdifference between cannula and catheterproducers surplus definitionexplain the process of double fertilizationwhat are nouns and pronounshow are lipids and carbohydrates differentdiffusion and osmosis definitionsrough and smooth endoplasmic reticulumwhat are the wavelengths of x rays and gamma rayscaesura examplewhat is absorbance in spectrophotometrystatic equilibrium definition chemistrychamfer definitioninfinitive phrase definesimple versus fractional distillationpolar vs nonpolar substanceswhat is difference between inquiry and enquiryboson and fermionfinite verbs and nonfinite verbsconsumer surplus explanationarchaea and eubacteriathe function of nucleoplasmdifference between heterogeneous and homogeneous mixturefue imperfectproperties of ldpe and hdpewilliam shakespeare difference between comedy and tragedymoose and deer differenceglucose and fructose structuresdifference between schizophrenia and depressionbep calculationdefine sex chromosomewhat is the difference between pasta and macaronidefine pixiegumpaste and fondantorganic molasses vs blackstrap molassessomatic cells definitionethanoic acid from ethanoldefinition of recession and depressionpredicate nominative definitionmetonymy metaphorwhat is the formula for cpisemantics vs syntaxhow to identify a rolexwhat is the difference between renewable and nonrenewable resourcesprojectile motion numericalsfunction of rough and smooth endoplasmic reticulum