EVERYDAY SCIENCE

Detailed explanation-1: -A hydrometer is an instrument used to measure the relative density of liquids. It is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright.

Detailed explanation-2: -A hydrometer is an instrument used to measure the relative density (or specific gravity) of liquids that is, the ratio of the density of the liquid to the density of water.

Detailed explanation-3: -So, Hydrometer is used for measuring the density or relative density of liquids.

Detailed explanation-4: -hydrometer, device for measuring some characteristics of a liquid, such as its density (weight per unit volume) or specific gravity (weight per unit volume compared with water).

Detailed explanation-5: -A density bottle is any bottle of known volume which can be weighed empty and then weighed containing the liquid whose density you wish to determine. Then density = mass/volume and you thus determine density.