Density is the physical property that allows a cork to float on water. Briefly, cork is less dense than the water. In other words, it is lighter than water and, hence, it floats on the water.
Density is the ratio of mass to volume of a given substance. For example, the density of water is about 1 gram per milliliter (g/ml). In comparison, the density of cork is 0.24 gram per milliliter (g/ml). This means that cork is only 24% as heavy as water. This is the reason why cork floats on the surface of water.
This can also be explained in the terms of another property known as the specific gravity, which is the ratio of the density of a given substance to that of a standard fluid (generally, water). The specific gravity of cork is 0.24, which means that cork is lighter than water. As a result, it floats on the surface of the water.
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