Hydrometer — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

Also Known As	Specific gravity meter, densitometer (liquid), density meter, saccharometer (for sugar)

What is Hydrometer?

A hydrometer is an instrument used to measure the specific gravity (relative density) of liquids compared to water. It consists of a sealed glass tube with a weighted bulb at the bottom and a graduated stem that floats at different depths depending on the density of the liquid. The hydrometer reading is taken at the meniscus level of the liquid against the graduated scale.

Properties & Characteristics

Based on Archimedes' principle: floating depth inversely proportional to liquid density. Scale: usually reads specific gravity (1.000 for pure water at 4°C) or other units (Baumé, API gravity, Plato). Accuracy: ±0.001 specific gravity. Temperature correction required (usually calibrated at 15°C or 20°C).

Uses & Applications

Testing battery electrolyte (lead-acid batteries — sulfuric acid concentration). Brewing and winemaking (measuring sugar content/fermentation progress). Dairy industry (milk fat content). Antifreeze concentration in radiators. Sugar content in syrups. Urine specific gravity in medical testing. Quality control of liquids.

Safety Information

Glass hydrometers break easily — sharp glass hazard and chemical spill. Testing battery acid (sulfuric acid) requires gloves and eye protection. Some liquids tested (acids, solvents) may be hazardous. Temperature of liquid affects reading accuracy.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Hydrometer

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Synonyms Specific gravity meter, densitometer (liquid), density meter, saccharometer (for sugar)

Frequently Asked Questions

What is Hydrometer?

A hydrometer is an instrument used to measure the specific gravity (relative density) of liquids compared to water. It consists of a sealed glass tube with a weighted bulb at the bottom and a graduated stem that floats at different depths depending on the density of the liquid. The hydrometer reading is taken at the meniscus level of the liquid against the graduated scale.

What is Hydrometer used for?

Is Hydrometer hazardous?

More "H" Terms

Haber Process N₂ + 3H₂ ⇌ 2NH₃ | ΔH = −92 kJ/mol Hafnium Hf Half Cell Half Life Half-Cell E = E° − (RT/nF)lnQ Half-Life A(t) = A₀e^(−λt); t½ = ln2/λ Half-Reaction Halide X⁻ (e.g., F⁻, Cl⁻, Br⁻, I⁻) Halogen F₂, Cl₂, Br₂, I₂, At; Group 17; ns²np⁵ valence configuration Halogenation C-X + Cl₂/Br₂ (hv or AlCl₃) → C-X(halogen); EAS or radical pathway Halogens Hard Acid Hard acid: small, highly charged, low polarisability (e.g., H⁺, Mg²⁺, Al³⁺)

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