Whether an object sinks or floats in a liquid is determined by the relationship between the density of the object and the density of the liquid. The density of an object refers to how much mass it has per unit volume, while the density of a liquid refers to its mass per unit volume as well.
When an object is placed in a liquid, it experiences two forces: buoyancy and gravity. Buoyancy is the upward force exerted by a fluid on an object submerged in it, and it opposes the force of gravity pulling the object downward.
If the density of the object is greater than the density of the liquid, the object will sink. In this case, the force of gravity on the object is greater than the buoyant force exerted by the liquid, causing it to sink to the bottom.
On the other hand, if the density of the object is less than the density of the liquid, the object will float. In this case, the buoyant force exerted by the liquid is greater than the force of gravity on the object, resulting in it floating on the surface.
The key factor that determines whether an object will sink or float is the comparative densities of the object and the liquid. If the object is denser than the liquid, it will sink; if it is less dense, it will float. The concept can be summarized by Archimedes' principle, which states that an object will experience an upward buoyant force equal to the weight of the liquid it displaces.
It's important to note that the shape and size of the object can also affect whether it sinks or floats. An object with a large volume but low density, such as a ship, can float even though it is made of dense materials like steel, due to its overall shape and the presence of air-filled spaces that increase its average density.
In summary, the relative densities of the object and the liquid, along with the shape and size of the object, determine whether it sinks or floats in a given liquid.