Which one of the following instruments can be used to measured the density of a liquid? barometer hydrometer thermometer - Leaving Cert Physics - Question b - 2006

Among the instruments listed, the hydrometer is specifically designed to measure the density of liquids. It operates based on the principle of buoyancy, where the level to which the hydrometer sinks in the liquid corresponds to the density of that liquid. In contrast, a barometer measures atmospheric pressure, and a thermometer measures temperature.