* Density is a measure of how much mass is packed into a given volume. A denser object has more mass crammed into the same space.
* Floating depends on buoyancy. Buoyancy is the upward force exerted by a fluid (like water) on an object submerged in it.
* An object floats if the buoyant force is greater than or equal to the object's weight.
Here's the key relationship:
* If an object is less dense than the fluid it's in, it will float. The buoyant force will be stronger than the object's weight, pushing it upward.
* If an object is denser than the fluid it's in, it will sink. The buoyant force won't be strong enough to overcome the object's weight.
Example:
* A piece of wood is less dense than water, so it floats.
* A rock is denser than water, so it sinks.
Important Note: The shape of the object can also play a role in floating. A ship, for example, is made of steel which is denser than water, but its shape (hollow and wide) allows it to displace a large amount of water, creating enough buoyant force to float.
