Buoyancy Explanation

Ok, so basically buoyancy is defined as the upward force of water which allows objects to float. This force is exerted when an object is placed in water. The water level rises, and is displaced in a volume equal to that of the object.

For an object to completely float, the weight of the displaced water must be greater than that of the object. Therefore, dense objects will most likely not float. The reason objects are more buoyant in salt water than fresh water is that water containing dissolved salt in it is heavier. This means a greater mass of water is displaced, hence exerting a greater upward force, and causing an object to float.

So I can see two ways of testing buoyancy. I can compare the results of experimenting with objects of a differing mass:volume ratio, or I could simply change the amount of salt in the water. Or I could do both. Both experiments prove that buoyancy is determined by the mass of water displaced in relation to the mass of the object.