Here's a breakdown:

* Buoyancy is an upward force exerted by a fluid that opposes the weight of an immersed object.

* It's the reason why objects seem lighter in water, and why some objects float.

* The magnitude of the buoyant force is equal to the weight of the fluid displaced by the object, as stated by Archimedes' Principle.

Let me know if you'd like to explore Archimedes' Principle in more detail!