What hydrometer is made of
A float with a scale: the denser the liquid, the higher it floats. It is used to measure the density of milk, syrup or battery acid.
- Mercury — has part. Old hydrometers used mercury or lead shot as the weight to keep them upright.
- Archimedes’ principle — uses. A hydrometer floats: the buoyant force depends on the liquid's density, so how deep it sinks shows the density.
- Glass — is made of. A glass tube with a weight at the bottom and a scale at the top.