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# What is the specific weight?

We explain what the specific weight is and what are the formulas it uses. In addition, some examples and their relationship with density.

## What is the specific weight and its formula?

Specific gravity is the relationship between the weight and volume of a substance . Since the weight of an object is the extent to which the attraction of the Earth acts on it, and at the same time the volume is the surface that said object occupies, the specific weight constitutes the relationship between both properties expressed in Newtons per cubic meter (N / m 3 ), according to the International System.

The calculation of it, requires numerous other properties of the substance, such as density, mass and ordinary weight of the substance. This according to the following calculation formula, in which the specific weight is represented by the symbol gamma (γ) :

γ (specific weight) = w (ordinary weight) / V (volume of the substance), or what is the same: γ = w / V = ​​mg / V, where m is the mass of the substance and g is the acceleration of gravity (commonly considered as 9.8 m / s 2 ). From there it is concluded that: γ = pg, where p is the density of the substance.

According to the International Bureau of Weights and Measures (BIPM), however, this term is not acceptable, “weight density” should be used instead.

1. ### Examples of specific weight

Some examples of different materials are:

• Plaster: 1250 N / m 3
• Cal: 1000 N / m 3
• Dry sand: 1600 N / m 3
• Wet sand: 1800 N / m 3
• Loose cement: 1400 N / m 3
• Concrete slabs: 2200 N / m 3
• Poplar wood: 500 N / m 3
• Ash Wood: 650 N / m 3
• American pine wood: 800 N / m 3
• Steel: 7850 N / m 3
• Aluminum: 2700 N / m 3
• Bronze: 8600 N / m 3
• Lead : 11400 N / m 3
• Zinc: 7200 N / m 3
• Iron foundry: 7250 N / m 3
• Water : 1000 N / m 3
• Asphalt: 1300 N / m 3
• Stacked paper: 1100 N / m 3
• Slate: 2800 N / m 3
• Tar: 1200 N / m 3
• Granite: 2800 N / m 3

## Specific gravity and density

The relationship between specific gravity and density is the same as that between the weight and mass of a substance. The density has to do with the level of accumulation of matter in an object or substance, ie, the amount of material that comprises; and since the specific weight is nothing more than the force with which the Earth attracts a unit of mass of said matter, it is evident that a substance whose particles are denser together, that is, more compact than others, will be attracted with more force by gravity than other more dispersed particles.

## What is the difference between specific gravity and unit weight?

### Specific weight

The specific weight of a soil is its weight per unit of volume. The term is often used to characterize the solid part (particles) of a soil.

The units of specific gravity are: [F / L 3 ].

## Unit Weight

Unit weight is defined as the weight of a body per unit volume. The unit weight of the soil varies according to the water content of the soil, defined as: wet unit weight (unsaturated), saturated unit weight and dry unit weight.

The unit weight units are: [F / L3].

At this point, it is good to remember that when using a scale, it is mass, not weight, that is reported.

The weight is obtained if the mass is multiplied; due to the gravity of the place where you want to know this information.

In Geotechnical Analysis programs , such as: GEO5 , for geotechnical calculation, two values ​​are required:

• The unit weight of the soil, in its natural state, and
• The unit weight of the saturated soil.
The first value is used for all calculations, where the ground is not submerged. While below the water table , the unit weight of the saturated soil is used.

## What is the difference between mass and weight?

The mass is the amount of matter of bodies. Mass is measured in kilograms (kg) or grams (g). The mass is measured with the balance.

The weight is the force exerted by gravity on a mass. Weight is measured in newtons (N) or kilograms force. Weight is measured with the dynamometer.

## Tables of Specific Weights and Densities of Materials

### Specific Weights of Metals

 Metal Specific Weight (kg / m 3 ) steel sweet 7800 Cast steel 7860 Forged steel 7860 Extra mild steel 7850 Pure aluminum 2580 Aluminum beaten 2700 Cast aluminum 2600 Antimony 6690 Argentán 8400 to 8700 White cast iron 7400 Gray cast iron 7100 Cast bismuth 9500 to 9800 Liquid bismuth 10055 Bronze (8 to 14% Sn) 7400 to 8900 Aluminum bronze 7450 Bells bronze 8810 Cannon bronze 8440 to 9230 Nickel Bronze 8850 Phosphor bronze 8800 Cadmium 8650 Calcium 1580 Cobalt 8800 Cobalt powder 9500 Cast copper 8700 Chipped copper, rolled 8920 Drawn copper 8930 to 8950 Electrolytic copper 8900 Liquid copper 8220 Cast tin 7290 Whipped tin, rolled 7300 to 7500 Liquid tin 7025 Strontium 2600 Pure iron 7840 Cupola casting 7250 Liquid cast iron 6600 to 7000 Cast brass 8400 to 8700 Drawn brass (according to% zinc) 8430 to 8730 Laminated brass 8520 to 8620 Magnesium 1740 Manganese 7400 Mercury (at 0º) 13,600 White metal (from bearings) 7100 Delta metal 8600 Cast nickel 8680 Rolled nickel 8000 Molten gold 19250 Beaten gold 15300 to 19350 Native gold 15600 to 19350 Cast silver 10420 to 10530 Beaten silver 10530 Liquid silver 9510 German silver 8400 to 8700 Platinum beaten 21400 Cast platinum 21150 Solid lead 11370 Liquid lead 10640 Potassium 870 Sodium 978 Tungsten 19100 Cast zinc 6860 Rolled zinc 7190 Liquid zinc 6480 – –

### Specific Weights of Liquids

 Liquid Specific Weight (kg / m 3 ) Creosote oil 1100 Flax oil 930 Mineral oil 900 to 930 Olive oil 920 Castor oil 970 Acetone 790 Hydrochloric acid 1050 to 1200 Nitric acid 1250 to 1500 Sulfuric acid 1800 to 1900 Water 999.97 Heavy water 1107 Ethyl alcohol 800 Coal tar 1100 to 1200 Andean 1040 Benzine 680 to 720 Gasoil 675 Gasoline 750 Kerosene 790 to 820 Mercury 13,600 Naphtha 750 to 780 Paraffin 900 Raw oil 880 Refined petroleum 800 Resins in general 1070

### Wood Specific Weights

 Wood class Specific Weight (kg / m 3 ) Fir tree 600 Poplar 500 Carob tree 810 Calden 630 Mahogany 820 Chestnut 800 Cedar 750 Missionary cedar 550 Incense 920 Lapacho 1000 Walnut, Oak 800 Petiribi 650 White Pine 430 Missionary pine 510 Pino Neuquén 520 Oregon Pine 550 Spruce Pine 460 Pine Tea 600 White quebracho 910 Quebracho colorado 1280 Slavonian oak 750 Virapita 900 Viraro 920

### Specific Weights of Natural Rocks and Stones

 Stone Type Specific Weight (kg / m 3 ) Sandstone 2600 Porous sandstone and porous limestone 2400 Granite, sienna, porphyry 2800 Basalt, diorite 3000 Marble, slate 2800 Compact limestone 2700 Porous limestone 2400 Roof slate 2800 – –

### Specific Weights of Artificial Stones

 Stone Type Specific Weight (kg / m 3 ) Adobe 1600 Asbestos-cement 2000 Ceramic tile 1800 Stoneware tile 1900 Hydraulic tile 2100 Concrete 2200 Solid ceramic brick 1800 Perforated ceramic brick 1400 Hollow ceramic brick 1000 Slag brick 1400 Silico-limestone brick 1900

### Specific Weights of Construction Materials

 Material Specific Weight (kg / m 3 ) Internal Friction Angle Sand 1500 30th Pumice sand 700 35th Lime powder 1000 25th Lump lime 1000 45º Rubble or brick dust 1300 35th Cement in bags 1600 – Cement powder 1200 25th Coke ash 700 25th Cement clinker 1500 30th Blast Furnace Slag (granulated) 1100 25th Blast Furnace Slag (chopped) 1500 40th Gravel 1700 40th Plaster and plaster 1250 25th

### Specific Weights of Bulk Materials

 Material Specific Weight (kg / m 3 ) Dry land 1330 Wet land 1800 Saturated earth 2100 Dry sand 1600 Wet sand 1860 Saturated sand 2100 Gravel 1700 Dry boulders 1700 Wet boulders 2000 Split stone 1700 Cement 1400 Brick dust 900 Cast 970 – –

### Specific Weights of Combustible Materials

 Fuel type Specific Weight (kg / m 3 ) Internal Friction Angle Brown coal briquettes (stacked) 800 30th Brown coal briquettes (stacked) 1300 – Charcoal (in pieces) 400 45º Coal coke 500 45º Raw coal (with mine moisture) 1000 45º Pulverized coal 700 25th Coal in laundry waste 1200 0º Coal in other forms 850 30th Wood chips 200 45º Chopped firewood 400 45º Lignite 700 35th Seated wood sawdust 250 45º Loose wood sawdust 150 45º

### Specific Weights of Storable Agricultural Products

 Product Specific Weight (kg / m 3 ) Internal Friction Angle Oatmeal 450 30th Sugar 750 35th Barley 650 25th Rye 800 35th Green peas 800 25th Flour 500 45º Pressed hay 170 – Jewish 750 30th Corn 750 25th Crushed malt 400 45º Potatoes 750 30th Sugar beet, dried and sliced 300 40th Beets, turnips, carrots 750 30th Semolina 550 30th Wheat 750 25th

### Specific Weights of Other Storable Products

 Product Specific Weight (kg / m 3 ) Internal Friction Angle Artificial fertilizers 1200 40th Carbide 900 30th Caked manure 1800 45º Loose manure 1200 45º Fish flour 800 45º Ice 900 30th Iron ore 3000 40th Pyrite 2700 45º Roasted pyrite 1400 45º Common salt 1200 40th

### Specific Weights of Other Materials

 Material Specific Weight (kg / m 3 ) Tar 1200 Asbestos 1200 Asphalt 1300 Garbage 660 Quicklime 1150 Demolition rubble 1200 Sheet rubber 1700 Ashes 900 Blast furnace slag 800 Ice 900 Common bricks 1350 to 1600 Pressed Machine Bricks 1580 Hollow bricks 1100 Refractory bricks 1850 Vitrified bricks 1600 to 2000 Paper 1100 Board 2700 Sheet plastic 2100 Porcelain 2400 Glass 2600 Cast 970 Plaster powder 1200

### Specific Weights of Types of Seating

 Ashlar Specific Weight (kg / m 3 ) Basalt 3000 Granite 2800 Compact limestone or marble 2800 Sandstone 2600 Porous sandstone or porous limestone 2400

### Brick and Block Factory Specific Weights

 Factory Type Specific Weight (kg / m 3 ) Solid ceramic brick factory 1800 Perforated ceramic brick factory 1500 Hollow Ceramic Brick Factory 1200 Ceramic Silico-Calcareous Brick Factory 2000 Hollow Block Mortar Factory (Heavy) 1600 Hollow mortar block factory (light) 1300 Gypsum hollow block factory 1000 – –

### Partition Specific Weights (uncoated)

 Partitions Specific Weight (kg / m 2 ) Rasilla partition (3 cm thick) 40 Hollow brick partition (4.5 cm thick) 60 Hollow brick partition (9 cm thick) 100 Hollow brick partition (12 cm thick) 140

### Specific Coating Weights (per cm of thickness)

 Coating Specific Weight (kg / m 2 ) Plaster or cement plaster twenty Lime plaster, stucco 16 Plaster trim 12 – –

### Specific Masonry Weights

 Masonry Type Specific Weight (kg / m 3 ) Common bricks with lime mixture 1600 Common bricks with cement mix 1800 Hollow bricks with lime mixture 1300 Hollow bricks with cement mix 1500 Machine bricks with lime mix 2000 Machine bricks with cement mix 2200 Bricks pressed with lime mixture 1900 Pressed bricks with cement mix 2100 Partitions of slag, char, etc. plastered with cement 1300 Refractory bricks 2700 Marble 2500 Limestone 2300 Granite 2600 Artificial stone 2100

### Specific Weights of Concretes and Concretes

 Concrete Type Specific Weight (kg / m 3 ) Made of cement, sand, pebbles, broken stone or granite pellets. Unassembled (en masse) 2300 Made of cement, sand, pebbles, broken stone or granite pellets. Armed (reinforced) 2500 Of cement, sand and brick rubble 1900 Slag 1600 – –

### Specific Weights of Mixes and Mortars

 Mixtures Specific Weight (kg / m 3 ) Cement and sand 2100 Cement, lime and sand 1900 Lime and sand 1700 Lime, sand and brick dust 1600 Cast plaster 1000 – – – –

### Specific Weights of Floors and Pavements

 Floors and Pavements Specific Weight (kg / m 2 ) Molten asphalt 14 (for each cm of thickness) Cement and marble tiles 22 (for each cm of thickness) Hydraulic or ceramic tile (Total thickness, including filling: 3 cm.) fifty Hydraulic or ceramic tile (Total thickness, including filling: 5 cm.) 80 Hydraulic or ceramic tile (Total thickness, including filling: 7 cm.) 110 Agglomerated cork on a 2 cm platform . with batten 40 Linoleum or rubber tiles on 2 cm layer of mortar. fifty 2 cm platform. on batten received with plaster 30 Terrazzo on mortar (5 cm. Total thickness) 80 Parquet on 2 cm platform. and track 40

### Specific Weights of Roofs and Construction Elements

 Cover Type Specific Weight (kg / m 2 ) Simple flat roof tiles with support reinforcement 75 Double flat roof tiles with support reinforcement 95 Spanish tiles with support armor 105 English slate roof over slatted Four. Five English slate roof on 2.5 cm thick boards 55 Zinc in 0.7 mm thick sheet metal on boards 40 0.6 mm thick sheet copper on boards 40 4mm thick unarmored glass 30 Glass shingles with support reinforcement 65 Corrugated iron sheet 10 8mm thick fiber cement corrugated sheet twenty 6mm thick fiber cement corrugated sheet fifteen

### Specific weights of floors and floors

 Other Cover Materials Material Specific Weight (kg / m 2 ) One layer of tarred cardboard 5 Two layers of tarred cardboard fifteen Slate (1/2 view) twenty Slate (1/3 view) 30 Corrugated fibroasphalt sheet 5 Corrugated fiber cement sheet fifteen Zinc plate (1 to 1.2 mm thick) 10 Light curved roof tile (1.6 kg per piece) 40 Standard curved tile (2.0 kg per piece) fifty Heavy curved tile (2.4 kg per piece) 60 Light flat tile (2.4 kg per piece) 30 Regular flat tile (3.0 kg per piece) 40 Heavy flat tile (3.6 kg per piece) fifty

### Specific Ceiling Weights

 Types of Ceilings Specific Weight (kg / m 2 ) plaster with batten twenty cement, lime and sand with expanded metal 57 plastered plaster 5 – –

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