What is Comparative density?

Answer 1

Density = mass / volume

The density of an object affects how it will float in another. Example the density of hydrogen is ~ 0.08 g / L whereas the density of air is ~ 1.2 g/L. Therefore, hydrogen floats in air.

For an object to float in water it has to have a density less than 1.0 g/mL or 1.0kg/L.

1. densities can be compared to see if an object will float.
2. densities of pure substance can be checked with reference books or online. If a substance is impure then its density will not be the same as the reference value. Densities can be compared to check if the substance is pure. When Indiana Jones replaced a block of gold with an equal volume of water to avoid a trap springing would not have worked. Why? Density of gold is 19.3 times heavier than an equal volume of water.