The upward force exerted by a fluid that opposes the weight of an immersed or submerged object.

Here's a breakdown:

* Fluid: A substance that can flow, like liquids and gases.

* Immersed: Partially submerged in the fluid.

* Submerged: Completely covered by the fluid.

Archimedes' Principle explains how buoyant force works:

* The buoyant force on an object is equal to the weight of the fluid that the object displaces.

This means that:

* The more fluid an object displaces, the greater the buoyant force.

* If an object is denser than the fluid, it will sink because its weight exceeds the buoyant force.

* If an object is less dense than the fluid, it will float because the buoyant force is greater than its weight.

Here's an example:

Imagine a boat floating in water. The boat displaces a certain amount of water, and the buoyant force acting on the boat is equal to the weight of that displaced water. If the boat's weight is less than the weight of the water it displaces, it will float.

Buoyant force is a fundamental concept in fluid mechanics and has many applications in engineering, physics, and everyday life.