States & mixtures
Density — ঘনত্ব
Quick answer
Mass packed into each unit of volume; every pure substance has its own density, so it works like a fingerprint.
Definition
Density tells how much mass is packed into a certain volume: density = mass ÷ volume, usually written in g/cm³ for solids and liquids. Every pure substance has its own density, so chemists use it as a fingerprint — gold at 19.3 g/cm³ is about seven times denser than aluminium. An object floats in a fluid when it is less dense than that fluid, which is why ice, slightly lighter than water, floats on a river.
For example
A lump of pure gold feels startlingly heavy because 19.3 g squeezes into every cm³; the same volume of iron holds only about 7.9 g.