What does density mean What is density?

In physics, the mass of a substance per unit volume is called the density of that substance.

1. The ratio of the mass of a substance to its volume, that is, the mass of a substance per unit volume, is called the density of such a substance. Symbol. The unit is kilogram meter 3.

Its mathematical expression is =m v. In the International System of Units, the principal unit of mass is the kilogram and the principal unit of volume is the cubic meter, so the mass of 1 cubic meter of matter is taken as the density of the substance. For inhomogeneous substances, this is called "average density".

2. The physical meaning of density. For example, the density of water at 4 is 10 3 kg m 3 or 1 g cm 3 (, physical) meaning is: the mass of water per cubic meter is kg.

The average density of the Earth is kilogram m3.

The average density of dry air under standard conditions is 3 kilograms.

Density of common non-metallic solids, metals, liquids, gases (omitted).

3.Refers to the mass of a substance contained in a unit volume at a specified temperature, expressed in kg m 3 (read as kilograms per cubic meter) or g cm 3 (read as grams per cubic centimeter). It is mainly used for the measurement of conversion quantity and delivery acceptance, the quality control of certain oil products, and the simple judgment of oil performance.

Density, said among the people"Specific gravity"

The density of water, i.e., the specific gravity of water, is 1000 kg m3

The principal unit of density in the International System of Units is "kilogram meter 3", which is something that most students can master, but many students find it difficult to convert units. For example, the density of iron is 78 103 kg m3 g cm3.

This problem can be solved by using the basic method in unit conversion, that is, how many times the unit in the molecule becomes smaller, and the converted value becomes several times larger: 1 kilogram 103 grams; How many times the unit in the denominator becomes smaller, and how many times the converted value becomes: 1 m 3 106 cm 3, thus, 7 8 10 kg m 3 7 8 103 (103 106) g cm 3 7 8 g cm3; According to this conversion method; There is a law in the unit of density that can be concluded by analyzing, namely:

For the density of a substance, the values are the same when the units are used as "gram centimeters3", "kilogram decimeters3", and "tons of meters3", respectively. For example, the density of iron, according to this law, can be known: water 7 8 g cm 3 7 8 kg decim 3 7 8 tons m3.

This "7 8" is obtained by removing 103 from the density value of iron in the density table in the textbook. Keeping this rule in mind not only brings great convenience to the conversion of density units, but also makes some problems involving density calculations simpler. For example, if you use this method to calculate the mass of water, the mass of 1 cm3 (ml) of water is 1 gram, the mass of 1 decimeter3 (liter) of water is 1 kg, and the mass of 1 meter3 of water is 1 ton.

The density of substances is generally different from the molecular gap and weight of different substances.

Density is a measure of the mass within a particular volume, density is equal to the mass of an object divided by the volume, which can be represented by symbols. In the International System of Units and the Chinese legal unit of measurement, the unit of density is kg m3.

m is the mass of the volume element. In centimeter-gram-second, density is measured in grams of cubic centimeters; In the International System of Units and the Chinese legal unit of measurement, the unit of density is kilogram cubic meter.

Introduction

The density of the human body is only g cm, which is only a little more dense than water. Gasoline is less dense than water, so oil stains you see on the road will float on the water. Seawater is denser than water, so it is easier for the human body to float in seawater.

The density of the Dead Sea reaches a density greater than that of the human body, so people can float in the Dead Sea.

It is an important criterion for density. In agriculture, it can be used to judge the fertility of the soil, and the soil with more humus is fertile, and its density is generally kilograms. When we select seeds, we can select seeds according to the sinking and floating conditions of seeds in the water

The plump and robust seeds sink due to their high density; Deflated husks and other weed seeds float on the surface of the water due to their low density. In industrial production, for example, the production of starch uses potatoes as raw materials, and generally speaking, the density of potatoes with more starch is larger, so the yield of starch can be estimated by measuring the density of potatoes.

1. Definitions. 1. Density is the mass of a material per unit volume in an absolutely dense state. The so-called volume in the absolute dense state is the volume that does not contain any pores.

2. Apparent density indicates the mass of the material per unit meso-volume (including internal closed pores). Bulk density represents the mass of a material's unit macroscopic volume, including internal closed and open pores.

3. Bulk density refers to the mass of bulk material or powdery material per unit volume in the natural stacking state. The stacked volume of the material refers to the volume of the container in a natural and loose state according to a certain method, including the volume of particles and the volume of the voids between the particles.

2. Differences. 1. The scope of the expression object is different.

Density is a broad concept that can denote the density of all substances; Apparent density and bulk density refer to the density under specific material conditions.

2. The measurement method is different.

Density determination can be done using the specific gravity cup method, Archimedes' law, buoyancy method, density meter method, etc. Apparent density: For materials with regular shapes, volume is measured directly; For irregularly shaped materials, the pores can be closed by wax sealing, followed by volume measurement by draining. Bulk density is generally the measured volume mass of an object in a container just after it has been filled.

Density is a measure of the mass within a specific volume. The definition of density is the mass of an object divided by its volume.

Calculation formula: =m v

Unit: g cm or kg m

Symbol.

The ratio of the mass of an object of a substance to its volume is called the density of that substance.

Summary. Density is a measure of the mass within a specific volume, density is equal to the mass of an object divided by the volume, which can be expressed by the symbol (pronounced rho), in the International System of Units and the Chinese legal unit of measurement, the unit of density is kilograms per cubic meter, and the symbol is kg m3

What does density mean?

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Density is a measure of the mass within a specific volume, density is equal to the mass of an object divided by the volume, which can be expressed by the symbol (pronounced rho), in the International System of Units and the Chinese legal unit of measurement, the unit of density is kilograms per cubic meter, and the symbol is kg m3

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Density is a physical quantity that represents the ratio of the mass to volume of a substance. It is usually measured in grams per cubic centimeter (g cm 3) or grams per liter (g l).There are also other units like mass density (kg m 3) and linear density (kg m).

Density can be used to compare the density similarity of a substance, and if the density of two substances is equal, then at the same volume, both have the same mass. Density is also an important factor in many physical and chemical phenomena, such as the rise and fall of matter in the gravitational field, the pressure difference between liquids and gases, etc.

Summary. Density.

Precise power. degree, refers to the degree of star, the degree of the degree.

Hanshu Legal Calendar I": "The surname and other music cannot be counted, and those who are willing to recruit and govern the calendar will make more density, increase or decrease each other, and create the Han "Taichu Calendar". ”

The degree of intensity.

Wei Wei, Chapter 15 of Part 5 of "The East": "It can be fully explained how fierce the battle was at that time, and how amazing the density of artillery fire on both sides was. ”

The ratio of the mass of a substance to its volume is called the density of the substance, i.e., the mass contained in a unit volume, expressed in grams of cubic centimeters.

What does density mean?

Density. Precise power. degree, refers to the degree of star, the degree of the degree.

Hanshu Legal Calendar I": "The surname and other music cannot be counted, and those who are willing to recruit and govern the calendar will make more density, increase or decrease each other, and create the Han "Taichu Calendar". ”

The degree of intensity.

Wei Wei, Chapter 15 of Part 5 of "The East": "It can be fully explained how fierce the battle was at that time, and how amazing the density of artillery fire on both sides was. ”

The ratio of the mass of a substance to its volume is called the density of the substance, i.e., the mass contained in a unit volume, expressed in grams of cubic centimeters.

Explanation of density trace search [density] usually refers to the distribution of quantities (e.g., mass, electricity, energy) of each spatial unit (e.g., area, length, volume) - called areal density, linear density, and volume density respectively Detailed explanation (1).Precise power. degree, refers to the degree of star, the degree of the degree.

Hanshu Legal Calendar I": "The surname and other music cannot be counted, and those who are willing to recruit and govern the calendar will make more density, increase or decrease each other, and create the Han "Taichu Calendar". 2).

The degree of intensity. Wei Wei, Chapter 15 of Part 5 of "The East": "It can be fully explained how fierce the battle was at that time, and how amazing the density of artillery fire on both sides was.

3).The ratio of the mass of a substance to its volume is called the density of the substance, i.e., the mass contained in a unit volume, expressed in grams of cubic centimeters. Word decomposition Explanation of dense dense dense ì thick, small void, as opposed to "sparse" and "sparse".

Tightness. Dense. Dense.

Tight. Seal. Densely packed.

Dense. Dense turns. Intensive drumming (a metaphor for the active and intense preparation before the official event, also known as "intensive drumming").

Close relationship, good relationship: close friends. Close relatives.

Non-disclosure of omissions, non-disclosure of the interpretation of the degree ù Calculation of the length of the apparatus or unit: scale. Carved hand.

Weights and measures. The state that a thing has reached: the degree.

Height. Demeanor. The unit of the angle of the circle, a circumferential angle is divided into degrees:

Angle. The unit that is calculated according to a certain criterion: temperature.

Humidity. Longitude. Latitude.

Concentration. Units of electrical energy,