Buoyancy vs. Upthrust — What's the Difference?
By Tayyaba Rehman & Urooj Arif — Updated on March 20, 2024
Buoyancy is a force that causes objects to float or rise in a fluid, depending on density differences; upthrust is the specific upward force exerted by a fluid on an object submerged in it.
Difference Between Buoyancy and Upthrust
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Key Differences
Buoyancy refers to the overall ability of a fluid to exert an upward force on any object placed in it, allowing the object to float or sink based on its density relative to the fluid. On the other hand, upthrust is the term used to describe the specific force that acts in the upward direction against gravity, enabling an object to float or remain submerged without sinking to the bottom.
While buoyancy is a principle that explains why objects float or sink, upthrust is the actual force experienced by the object in the fluid. Buoyancy depends on the density of both the fluid and the object, whereas upthrust is a direct measurement of the force exerted by the fluid on the object.
Buoyancy is determined by factors such as the volume of the object submerged in the fluid and the density difference between the object and the fluid. In contrast, upthrust is calculated based on the volume of the fluid displaced by the object and is directly influenced by the fluid's density.
In practical applications, buoyancy is considered when designing ships, submarines, and balloons to ensure they float or can be controlled within a fluid medium. Upthrust, meanwhile, is crucial in determining the exact force needed to keep these objects afloat or to achieve buoyancy in a given fluid environment.
Both buoyancy and upthrust are governed by Archimedes' principle, which states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces. However, buoyancy focuses more on the principle's application in determining whether an object floats or sinks, while upthrust deals with quantifying the specific force exerted.
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Comparison Chart
Definition
The ability of a fluid to exert an upward force on an object, influencing its ability to float or sink.
The specific upward force exerted by a fluid on an object.
Based On
Density differences between the object and the fluid.
Volume of the fluid displaced by the object.
Calculation Factors
Object's volume, fluid's density, and gravity.
Displaced fluid's volume and density.
Practical Applications
Designing ships, submarines, balloons for floatation control.
Calculating force needed for floatation or submerged stability.
Governed By
Archimedes' principle in a general sense.
Archimedes' principle in a specific force measurement.
Compare with Definitions
Buoyancy
A measure of an object's ability to float.
Saltwater offers more buoyancy than freshwater due to its density.
Upthrust
The force measured to calculate an object's floatation capability.
Submarines adjust their buoyancy to control upthrust.
Buoyancy
The force that allows objects to float in a fluid.
The buoyancy of water helps swimmers stay afloat.
Upthrust
The specific force that opposes gravity in fluids.
Upthrust allows balloons to rise in the air.
Buoyancy
The principle determining whether an object will float or sink.
Engineers consider buoyancy when designing boats.
Upthrust
The upward force exerted by a fluid on a submerged object.
Upthrust keeps ships floating on the ocean.
Buoyancy
The upward force exerted by a fluid.
Buoyancy counteracts an object's weight in a fluid.
Upthrust
A direct result of fluid displacement by an object.
Upthrust is felt when you push a ball underwater and release it.
Buoyancy
The effect of fluid density on floating objects.
Buoyancy is why ice cubes float in a drink.
Upthrust
Calculated based on displaced fluid volume.
Divers experience upthrust as a lifting sensation underwater.
Buoyancy
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid.
Upthrust
An upward thrust, especially of part of the earth's crust.
Buoyancy
The tendency or capacity to remain afloat in a liquid or rise in air or gas.
Upthrust
To thrust or be thrusted upward. Used especially of the earth's crust.
Buoyancy
The upward force that a fluid exerts on an object less dense than itself.
Upthrust
An upward thrust.
Buoyancy
Ability to recover quickly from setbacks; resilience.
Upthrust
(nautical) Buoyancy.
Buoyancy
Lightness of spirit; cheerfulness.
Upthrust
(geology) An upward movement of part of the Earth's crust.
Buoyancy
(physics) The upward force on a body immersed or partly immersed in a fluid.
Upthrust
(transitive) To thrust something upwards.
Buoyancy
The ability of an object to stay afloat in a fluid.
Upthrust
(intransitive) To be thrust upwards.
Buoyancy
(by extension) Resilience or cheerfulness.
Upthrust
(geology) a rise of land to a higher elevation (as in the process of mountain building)
Buoyancy
The property of floating on the surface of a liquid, or in a fluid, as in the atmosphere; specific lightness, which is inversely as the weight compared with that of an equal volume of water.
Buoyancy
The upward pressure exerted upon a floating body by a fluid, which is equal to the weight of the body; hence, also, the weight of a floating body, as measured by the volume of fluid displaced.
Such are buoyancies or displacements of the different classes of her majesty's ships.
Buoyancy
Cheerfulness; vivacity; liveliness; sprightliness; - the opposite of heaviness; as, buoyancy of spirits.
Buoyancy
Cheerfulness that bubbles to the surface
Buoyancy
The property of something weightless and insubstantial
Buoyancy
Irrepressible liveliness and good spirit;
I admired his bouyancy and persistent good humor
Common Curiosities
What is upthrust?
Upthrust is the specific upward force that a fluid exerts on an object submerged in it, contributing to the object's ability to float.
How do submarines control their buoyancy?
Submarines control buoyancy by adjusting their ballast tanks, filling them with water to sink or air to rise, manipulating the upthrust.
Is buoyancy only applicable in water?
No, buoyancy applies in any fluid, including gases like air, where it explains the floating of balloons and airships.
How is upthrust calculated?
Upthrust is calculated by multiplying the volume of fluid displaced by the object with the density of the fluid and gravitational acceleration.
What role does Archimedes' principle play in buoyancy and upthrust?
Archimedes' principle is fundamental to understanding both buoyancy and upthrust, stating that the buoyant force on an object is equal to the weight of the fluid displaced by the object.
How do birds experience upthrust in air?
Birds experience upthrust in air through lift generated by their wings, similar to how upthrust works in water but through aerodynamic principles.
What is buoyancy?
Buoyancy is the force exerted by a fluid that supports the weight of an object immersed in it, determining whether the object floats or sinks.
How do fish use buoyancy?
Fish adjust their buoyancy through an internal air bladder, allowing them to remain at a constant depth without expending energy.
What factors affect upthrust?
Upthrust is affected by the volume of fluid displaced, the density of the fluid, and gravitational force.
How is buoyancy related to density?
Buoyancy depends on the density difference between an object and the fluid it is in; objects less dense than the fluid float, while denser objects sink.
Can upthrust be negative?
Upthrust is generally considered a positive force acting upwards against gravity; it does not become negative but can be less than the weight of the object, causing it to sink.
What is the difference between buoyancy and flotation?
Buoyancy is the force that determines an object's ability to float, while flotation is the condition of an object when it is floating.
Do heavier objects have less buoyancy?
Heavier objects can still experience buoyancy if their overall density is less than the fluid's density or they displace enough fluid to generate sufficient upthrust.
Why do ships float despite their weight?
Ships float due to buoyancy; they displace a volume of water that weighs more than the ship itself, resulting in a net upward force or upthrust that supports them.
Why do icebergs float?
Icebergs float because ice is less dense than liquid water, resulting in positive buoyancy where the upthrust force exceeds the weight of the iceberg.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
