ounces per cubic inch (oz/in3) to tonnes per cubic meter (t/m3) conversion

What is the Ounce per Cubic Inch?

The ounce per cubic inch is a unit of density in the imperial and US customary systems, expressing the mass in avoirdupois ounces contained in one cubic inch of a substance. It is used mainly in engineering and materials work where both mass and volume are stated in customary units.

Definition

One ounce per cubic inch equals the mass of one avoirdupois ounce (28.349523125 g) divided by the volume of one cubic inch (16.387064 cm³).

$$1\ \text{oz/in3} = 1729.99\ \text{kg/m}^3$$

Because one cubic inch is defined exactly as 16.387064 cm³ and one avoirdupois ounce as exactly 28.349523125 g, the conversion is exact: 1 oz/in³ = 1.72999 g/cm³ = 1729.99 kg/m³. This should not be confused with the fluid-ounce-based densities used for liquids.

Origin and History

The unit derives from the avoirdupois ounce, standardized in England and later fixed to the metric system when the international yard and pound were defined in 1959 (1 pound = 0.45359237 kg exactly, hence 1 ounce = 1/16 pound). Combining this mass with the cubic inch produced a natural density measure for machinists and metallurgists working in inches.

Law and Notable Facts

The ounce per cubic inch is a derived unit with no independent legal definition; it follows automatically from the exact definitions of the avoirdupois ounce and the international inch. Because 1 oz/in³ ≈ 1.73 g/cm³, it produces conveniently sized numbers for dense materials.

Real-World Examples and Conversions

• Water (1.000 g/cm³) is about 0.578 oz/in³.
• Aluminium (2.70 g/cm³) is roughly 1.56 oz/in³.
• Steel (about 7.85 g/cm³) is close to 4.54 oz/in³.
• Lead (11.34 g/cm³) is about 6.55 oz/in³.

What is the Tonne per Cubic Meter?

The tonne per cubic meter is a metric unit of mass density, giving the number of metric tonnes of mass contained in one cubic meter of volume. It is common in civil engineering, mining, and bulk-materials handling, where masses are large.

Definition

One tonne per cubic meter equals one metric tonne (1000 kilograms) spread over one cubic meter. In SI base units:

$$1\ \text{t/m}^3 = 1000\ \text{kg/m}^3$$

This makes the tonne per cubic meter numerically equal to the kilogram per liter and to the gram per cubic centimeter, so pure water is very close to 1 t/m³.

Origin and History

The metric tonne (1000 kg) was adopted alongside the metric system to handle industrial-scale masses, and pairing it with the cubic meter—the coherent SI unit of volume—produced a convenient large-scale density unit. It became standard in continental European engineering practice during the nineteenth and twentieth centuries.

Law and Notable Facts

The tonne is accepted for use with the SI, though "t/m³" is a derived combination rather than a coherent SI unit itself. A handy fact: because 1 t/m³ equals 1 kg/L, an engineer's "specific gravity" of a material relative to water reads directly as its density in t/m³.

Real-World Examples and Conversions

Fresh water is about 1.00 t/m³ and seawater about 1.025 t/m³. Ordinary structural concrete runs roughly 2.4 t/m³, while structural steel is about 7.85 t/m³. Dry loose sand is around 1.6 t/m³. To convert to pounds per cubic foot, multiply by 62.43.