De quoi est fait hydrometer
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 — a pour partie. Old hydrometers used mercury or lead shot as the weight to keep them upright.
- Principe d'Archimède — utilise. A hydrometer floats: the buoyant force depends on the liquid's density, so how deep it sinks shows the density.
- Glass — est fait de. A glass tube with a weight at the bottom and a scale at the top.