Here's why:

* Buoyancy is an upward force exerted by a fluid (like water or air) that opposes the weight of an immersed object.

* Gravity is the force that pulls everything towards the center of the Earth.

When an object is submerged in a fluid, it experiences both buoyancy and gravity.

* If the buoyant force is greater than the force of gravity, the object will float.

* If the force of gravity is greater than the buoyant force, the object will sink.

Think of it like this:

* Buoyancy is trying to push the object upwards.

* Gravity is trying to pull the object downwards.

The outcome depends on which force is stronger!