P what degree. Abbreviated notation of numerical quantities

Length and distance converter Mass converter Bulk and food volume converter Area converter Volume and units converter in culinary recipes Temperature converter Pressure converter, mechanical stress, Young's modulus Energy and work converter Power converter Force converter Time converter Converter linear speed Flat Angle Thermal Efficiency and Fuel Efficiency Converter Number Converter in Various Numeral Systems Quantity Unit Converter Information Exchange Rates Dimensions women's clothing and shoes Sizes of men's clothing and shoes Angular velocity and rotational speed converter Acceleration converter Angular acceleration converter Density converter Specific volume converter Moment of inertia converter Torque converter Torque converter Specific heat of combustion converter (by mass) Converter of energy density and specific heat of combustion of fuel (by mass) Temperature difference converter Thermal expansion coefficient converter Thermal resistance converter Thermal conductivity converter Specific heat capacity converter Energy exposure and thermal radiation power converter Heat flux density converter Heat transfer coefficient converter Volume flow rate converter Mass flow rate converter Molar flow rate converter Mass flow density converter Molar concentration converter Mass converter concentration in solution Dynamic (absolute) viscosity converter Kinematic viscosity converter Surface tension converter Vapor permeability converter Vapor permeability and vapor transfer rate converter Sound level converter Microphone sensitivity converter Sound pressure level (SPL) converter Sound pressure level converter with selectable reference pressure Brightness converter Luminous intensity converter Illumination Converter Resolution Converter to computer graphics Frequency and wavelength converter Optical power in diopters and focal length Optical power in diopters and lens magnification (×) Converter electric charge Linear Charge Density Converter Surface Charge Density Converter Volume Charge Density Converter Converter electric current Linear current density converter Surface current density converter Electric field strength converter Electrostatic potential and voltage converter Converter electrical resistance Electrical resistivity converter Electrical conductivity converter Electrical conductivity converter Electrical capacitance Inductance converter American wire gauge converter Levels in dBm (dBm or dBmW), dBV (dBV), watts and other units Magnetomotive force converter Voltage converter magnetic field Magnetic flux converter Magnetic induction converter Radiation. Absorbed dose rate converter ionizing radiation Radioactivity. Radioactive decay converter Radiation. Exposure dose converter Radiation. Absorbed Dose Converter Decimal Prefix Converter Data Transfer Typography and Image Processing Units Converter Timber Volume Units Converter Calculation molar mass Periodic table of chemical elements by D. I. Mendeleev

1 milli [m] = 1000 micro [µ]

Initial value

Converted value

without prefix yotta zetta exa peta tera giga mega kilo hecto deca deci centi milli micro nano pico femto atto zepto yocto

Metric system and International system units (SI)

Introduction

In this article we will talk about the metric system and its history. We will see how and why it began and how it gradually evolved into what we have today. We will also look at the SI system, which was developed from the metric system of measures.

For our ancestors, who lived in a world full of dangers, the ability to measure various quantities in their natural habitat made it possible to get closer to understanding the essence of natural phenomena, knowledge of their environment and the ability to somehow influence what surrounded them. That is why people tried to invent and improve various measurement systems. At the dawn of human development, having a measurement system was no less important than it is now. Fulfill different measurements was necessary when building housing, sewing clothes different sizes, cooking and, of course, trade and exchange could not do without measurement! Many believe that the creation and adoption of the International System of SI Units is the most serious achievement not only of science and technology, but also of human development in general.

Early measurement systems

IN early systems In all measures and number systems, people used traditional objects to measure and compare. For example, it is believed that decimal system appeared due to the fact that we have ten fingers and toes. Our hands are always with us - that's why since ancient times people have used (and still use) fingers for counting. Still, we haven't always used the base 10 system for counting, and the metric system is a relatively new invention. Each region developed its own systems of units and, although these systems have much in common, most systems are still so different that converting units of measurement from one system to another has always been a problem. This problem became more and more serious as trade between different peoples developed.

The accuracy of the first systems of weights and measures directly depended on the size of the objects that surrounded the people who developed these systems. It is clear that the measurements were inaccurate, since the “measuring devices” did not have exact dimensions. For example, parts of the body were commonly used as a measure of length; mass and volume were measured using the volume and mass of seeds and other small objects whose dimensions were more or less the same. Below we will take a closer look at such units.

Length measures

In ancient Egypt, length was first measured simply elbows, and later with royal elbows. The length of the elbow was determined as the distance from the bend of the elbow to the end of the extended middle finger. Thus, the royal cubit was defined as the cubit of the reigning pharaoh. A model cubit was created and made available to the general public so that everyone could make their own length measures. This, of course, was an arbitrary unit that changed when a new reigning person took the throne. Used in Ancient Babylon similar system, but with minor differences.

The elbow was divided into smaller units: palm, hand, zerets(ft), and you(finger), which were represented by the widths of the palm, hand (with thumb), foot and finger, respectively. At the same time, they decided to agree on how many fingers there were in the palm (4), in the hand (5) and in the elbow (28 in Egypt and 30 in Babylon). It was more convenient and more accurate than measuring ratios every time.

Measures of mass and weight

Weight measures were also based on the parameters of various objects. Seeds, grains, beans and similar items were used as weight measures. A classic example of a unit of mass that is still used today is carat. Carats are now used to measure mass. precious stones and pearls, and once upon a time the weight of carob seeds, otherwise called carob, was determined as a carat. The tree is cultivated in the Mediterranean, and its seeds are distinguished by their constant mass, so they were convenient to use as a measure of weight and mass. IN different places different seeds were used as small units of weight, and larger units were usually multiples of smaller units. Archaeologists often find similar large weights, usually made of stone. They consisted of 60, 100 and other numbers of small units. Because the single standard the number of small units, as well as their weight, was missing, this led to conflicts when sellers and buyers who lived in different places met.

Volume measures

Initially, volume was also measured using small objects. For example, the volume of a pot or jug ​​was determined by filling it to the top with small objects relative to the standard volume - like seeds. However, the lack of standardization led to the same problems when measuring volume as when measuring mass.

Evolution of various systems of measures

The ancient Greek system of measures was based on the ancient Egyptian and Babylonian ones, and the Romans created their system based on the ancient Greek one. Then, through fire and sword and, of course, through trade, these systems spread throughout Europe. It should be noted that here we are talking only about the most common systems. But there were many other systems of weights and measures, because exchange and trade were necessary for absolutely everyone. If there was no written language in the area or it was not customary to record the results of the exchange, then we can only guess at how these people measured volume and weight.

There are many regional variations in systems of measures and weights. This is due to their independent development and the influence of other systems on them as a result of trade and conquest. Various systems were not only in different countries, but often within the same country, where each trading city had its own, because local rulers did not want unification in order to maintain their power. As travel, trade, industry, and science developed, many countries sought to unify systems of weights and measures, at least within their own countries.

Already in the 13th century, and possibly earlier, scientists and philosophers discussed the creation of a unified measurement system. However, it was only after the French Revolution and the subsequent colonization of various regions of the world by France and others European countries, which already had their own systems of weights and measures, a new system was developed, adopted in most countries of the world. This new system was decimal metric system. It was based on the base 10, that is, for any physical quantity there was one basic unit in it, and all other units could be formed in a standard way using decimal prefixes. Each such fractional or multiple unit could be divided into ten smaller units, and these smaller units could in turn be divided into 10 even smaller units, and so on.

As we know, most early measurement systems were not based on base 10. The convenience of a system with base 10 is that the number system we are familiar with has the same base, which allows us to quickly and conveniently, using simple and familiar rules, convert from smaller units to big and vice versa. Many scientists believe that the choice of ten as the base of the number system is arbitrary and is connected only with the fact that we have ten fingers and if we had a different number of fingers, then we would probably use a different number system.

Metric system

In the early days of the metric system, man-made prototypes were used as measures of length and weight, as in previous systems. The metric system has evolved from a system based on material standards and dependence on their accuracy to a system based on natural phenomena and fundamental physical constants. For example, the time unit second was initially defined as a fraction of the tropical year 1900. The disadvantage of this definition was the impossibility experimental verification this constant in subsequent years. Therefore, the second was redefined as a certain number of periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the radioactive atom of cesium-133, which is at rest at 0 K. The unit of distance, the meter, was related to the wavelength of the line of the radiation spectrum of the isotope krypton-86, but later The meter was redefined as the distance that light travels in a vacuum in a period of time equal to 1/299,792,458 of a second.

The International System of Units (SI) was created based on the metric system. It should be noted that traditionally the metric system includes units of mass, length and time, but in the SI system the number of base units has been expanded to seven. We will discuss them below.

International System of Units (SI)

The International System of Units (SI) has seven basic units for measuring basic quantities (mass, time, length, luminous intensity, amount of matter, electric current, thermodynamic temperature). This kilogram(kg) to measure mass, second(c) to measure time, meter(m) to measure distance, candela(cd) to measure luminous intensity, mole(abbreviation mole) to measure the amount of a substance, ampere(A) to measure electric current, and kelvin(K) to measure temperature.

Currently, only the kilogram still has a man-made standard, while the remaining units are based on universal physical constants or natural phenomena. This is convenient because the physical constants or natural phenomena on which the units of measurement are based can be easily verified at any time; In addition, there is no danger of loss or damage to standards. There is also no need to create copies of standards to ensure their availability in different parts of the world. This eliminates errors associated with the accuracy of making copies of physical objects, and thus provides greater accuracy.

Decimal prefixes

To form multiples and submultiple units, differing from the base units of the SI system by a certain integer number of times, which is a power of ten, it uses prefixes attached to the name of the base unit. The following is a list of all currently used prefixes and the decimal factors they represent:

For example, 5 gigameters is equal to 5,000,000,000 meters, while 3 microcandelas is equal to 0.000003 candelas. It is interesting to note that, despite the presence of a prefix in the unit kilogram, it is the base unit of the SI. Therefore, the above prefixes are applied with the gram as if it were a base unit.

At the time of writing this article, there are only three countries that have not adopted the SI system: the United States, Liberia and Myanmar. In Canada and the UK, traditional units are still widely used, even though the SI system is the official unit system in these countries. It’s enough to go into a store and see price tags per pound of goods (it turns out cheaper!), or try to buy building materials measured in meters and kilograms. Will not work! Not to mention the packaging of goods, where everything is labeled in grams, kilograms and liters, but not in whole numbers, but converted from pounds, ounces, pints and quarts. Milk space in refrigerators is also calculated per half-gallon or gallon, not per liter milk carton.

Do you find it difficult to translate units of measurement from one language to another? Colleagues are ready to help you. Post a question in TCTerms and within a few minutes you will receive an answer.

Calculations for converting units in the converter " Decimal prefix converter" are performed using unitconversion.org functions.

Length and distance converter Mass converter Converter of volume measures of bulk products and food products Area converter Converter of volume and units of measurement in culinary recipes Temperature converter Converter of pressure, mechanical stress, Young's modulus Converter of energy and work Converter of power Converter of force Converter of time Linear speed converter Flat angle Converter thermal efficiency and fuel efficiency Converter of numbers in various number systems Converter of units of measurement of quantity of information Currency rates Women's clothing and shoe sizes Men's clothing and shoe sizes Angular velocity and rotation frequency converter Acceleration converter Angular acceleration converter Density converter Specific volume converter Moment of inertia converter Moment of force converter Torque converter Specific heat of combustion converter (by mass) Energy density and specific heat of combustion converter (by volume) Temperature difference converter Coefficient of thermal expansion converter Thermal resistance converter Thermal conductivity converter Specific heat capacity converter Energy exposure and thermal radiation power converter Heat flux density converter Heat transfer coefficient converter Volume flow rate converter Mass flow rate converter Molar flow rate converter Mass flow density converter Molar concentration converter Mass concentration in solution converter Dynamic (absolute) viscosity converter Kinematic viscosity converter Surface tension converter Vapor permeability converter Vapor permeability and vapor transfer rate converter Sound level converter Microphone sensitivity converter Sound Pressure Level (SPL) Converter Sound Pressure Level Converter with Selectable Reference Pressure Luminance Converter Luminous Intensity Converter Illuminance Converter Computer Graphics Resolution Converter Frequency and Wavelength Converter Diopter Power and Focal Length Diopter Power and Lens Magnification (×) Electric charge converter Linear charge density converter Surface charge density converter Volume charge density converter Electric current converter Linear current density converter Surface current density converter Electric field strength converter Electrostatic potential and voltage converter Electrical resistance converter Electrical resistivity converter Electrical conductivity converter Electrical conductivity converter Electrical capacitance Inductance converter American wire gauge converter Levels in dBm (dBm or dBm), dBV (dBV), watts, etc. units Magnetomotive force converter Magnetic field strength converter Magnetic flux converter Magnetic induction converter Radiation. Ionizing radiation absorbed dose rate converter Radioactivity. Radioactive decay converter Radiation. Exposure dose converter Radiation. Absorbed dose converter Decimal prefix converter Data transfer Typography and image processing unit converter Timber volume unit converter Calculation of molar mass D. I. Mendeleev’s periodic table of chemical elements

1 mega [M] = 0.001 giga [G]

Initial value

Converted value

without prefix yotta zetta exa peta tera giga mega kilo hecto deca deci santi milli micro nano pico femto atto zepto yocto

Metric system and International System of Units (SI)

Introduction

In this article we will talk about the metric system and its history. We will see how and why it began and how it gradually evolved into what we have today. We will also look at the SI system, which was developed from the metric system of measures.

For our ancestors, who lived in a world full of dangers, the ability to measure various quantities in their natural habitat made it possible to get closer to understanding the essence of natural phenomena, knowledge of their environment and the ability to somehow influence what surrounded them. That is why people tried to invent and improve various measurement systems. At the dawn of human development, having a measurement system was no less important than it is now. It was necessary to carry out various measurements when building housing, sewing clothes of different sizes, preparing food and, of course, trade and exchange could not do without measurement! Many believe that the creation and adoption of the International System of SI Units is the most serious achievement not only of science and technology, but also of human development in general.

Early measurement systems

In early measurement and number systems, people used traditional objects to measure and compare. For example, it is believed that the decimal system appeared due to the fact that we have ten fingers and toes. Our hands are always with us - that's why since ancient times people have used (and still use) fingers for counting. Still, we haven't always used the base 10 system for counting, and the metric system is a relatively new invention. Each region developed its own systems of units and, although these systems have much in common, most systems are still so different that converting units of measurement from one system to another has always been a problem. This problem became more and more serious as trade between different peoples developed.

The accuracy of the first systems of weights and measures directly depended on the size of the objects that surrounded the people who developed these systems. It is clear that the measurements were inaccurate, since the “measuring devices” did not have exact dimensions. For example, parts of the body were commonly used as a measure of length; mass and volume were measured using the volume and mass of seeds and other small objects whose dimensions were more or less the same. Below we will take a closer look at such units.

Length measures

In ancient Egypt, length was first measured simply elbows, and later with royal elbows. The length of the elbow was determined as the distance from the bend of the elbow to the end of the extended middle finger. Thus, the royal cubit was defined as the cubit of the reigning pharaoh. A model cubit was created and made available to the general public so that everyone could make their own length measures. This, of course, was an arbitrary unit that changed when a new reigning person took the throne. Ancient Babylon used a similar system, but with minor differences.

The elbow was divided into smaller units: palm, hand, zerets(ft), and you(finger), which were represented by the widths of the palm, hand (with thumb), foot and finger, respectively. At the same time, they decided to agree on how many fingers there were in the palm (4), in the hand (5) and in the elbow (28 in Egypt and 30 in Babylon). It was more convenient and more accurate than measuring ratios every time.

Measures of mass and weight

Weight measures were also based on the parameters of various objects. Seeds, grains, beans and similar items were used as weight measures. A classic example of a unit of mass that is still used today is carat. Nowadays, the weight of precious stones and pearls is measured in carats, and once upon a time the weight of carob seeds, otherwise called carob, was determined as a carat. The tree is cultivated in the Mediterranean, and its seeds are distinguished by their constant mass, so they were convenient to use as a measure of weight and mass. Different places used different seeds as small units of weight, and larger units were usually multiples of smaller units. Archaeologists often find similar large weights, usually made of stone. They consisted of 60, 100 and other numbers of small units. Since there was no uniform standard for the number of small units, as well as for their weight, this led to conflicts when sellers and buyers who lived in different places met.

Volume measures

Initially, volume was also measured using small objects. For example, the volume of a pot or jug ​​was determined by filling it to the top with small objects relative to the standard volume - like seeds. However, the lack of standardization led to the same problems when measuring volume as when measuring mass.

Evolution of various systems of measures

The ancient Greek system of measures was based on the ancient Egyptian and Babylonian ones, and the Romans created their system based on the ancient Greek one. Then, through fire and sword and, of course, through trade, these systems spread throughout Europe. It should be noted that here we are talking only about the most common systems. But there were many other systems of weights and measures, because exchange and trade were necessary for absolutely everyone. If there was no written language in the area or it was not customary to record the results of the exchange, then we can only guess at how these people measured volume and weight.

There are many regional variations in systems of measures and weights. This is due to their independent development and the influence of other systems on them as a result of trade and conquest. There were different systems not only in different countries, but often within the same country, where each trading city had its own, because local rulers did not want unification in order to maintain their power. As travel, trade, industry, and science developed, many countries sought to unify systems of weights and measures, at least within their own countries.

Already in the 13th century, and possibly earlier, scientists and philosophers discussed the creation of a unified measurement system. However, it was only after the French Revolution and the subsequent colonization of various regions of the world by France and other European countries, which already had their own systems of weights and measures, that a new system was developed, adopted in most countries of the world. This new system was decimal metric system. It was based on the base 10, that is, for any physical quantity there was one basic unit, and all other units could be formed in a standard way using decimal prefixes. Each such fractional or multiple unit could be divided into ten smaller units, and these smaller units could in turn be divided into 10 even smaller units, and so on.

As we know, most early measurement systems were not based on base 10. The convenience of a system with base 10 is that the number system we are familiar with has the same base, which allows us to quickly and conveniently, using simple and familiar rules, convert from smaller units to big and vice versa. Many scientists believe that the choice of ten as the base of the number system is arbitrary and is connected only with the fact that we have ten fingers and if we had a different number of fingers, then we would probably use a different number system.

Metric system

In the early days of the metric system, man-made prototypes were used as measures of length and weight, as in previous systems. The metric system has evolved from a system based on material standards and dependence on their accuracy to a system based on natural phenomena and fundamental physical constants. For example, the time unit second was initially defined as a fraction of the tropical year 1900. The disadvantage of this definition was the impossibility of experimental verification of this constant in subsequent years. Therefore, the second was redefined as a certain number of periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the radioactive atom of cesium-133, which is at rest at 0 K. The unit of distance, the meter, was related to the wavelength of the line of the radiation spectrum of the isotope krypton-86, but later The meter was redefined as the distance that light travels in a vacuum in a period of time equal to 1/299,792,458 of a second.

The International System of Units (SI) was created based on the metric system. It should be noted that traditionally the metric system includes units of mass, length and time, but in the SI system the number of base units has been expanded to seven. We will discuss them below.

International System of Units (SI)

The International System of Units (SI) has seven basic units for measuring basic quantities (mass, time, length, luminous intensity, amount of matter, electric current, thermodynamic temperature). This kilogram(kg) to measure mass, second(c) to measure time, meter(m) to measure distance, candela(cd) to measure luminous intensity, mole(abbreviation mole) to measure the amount of a substance, ampere(A) to measure electric current, and kelvin(K) to measure temperature.

Currently, only the kilogram still has a man-made standard, while the remaining units are based on universal physical constants or natural phenomena. This is convenient because the physical constants or natural phenomena on which the units of measurement are based can be easily verified at any time; In addition, there is no danger of loss or damage to standards. There is also no need to create copies of standards to ensure their availability in different parts of the world. This eliminates errors associated with the accuracy of making copies of physical objects, and thus provides greater accuracy.

Decimal prefixes

To form multiples and submultiples that differ from the base units of the SI system by a certain integer number of times, which is a power of ten, it uses prefixes attached to the name of the base unit. The following is a list of all currently used prefixes and the decimal factors they represent:

For example, 5 gigameters is equal to 5,000,000,000 meters, while 3 microcandelas is equal to 0.000003 candelas. It is interesting to note that, despite the presence of a prefix in the unit kilogram, it is the base unit of the SI. Therefore, the above prefixes are applied with the gram as if it were a base unit.

At the time of writing this article, there are only three countries that have not adopted the SI system: the United States, Liberia and Myanmar. In Canada and the UK, traditional units are still widely used, even though the SI system is the official unit system in these countries. It’s enough to go into a store and see price tags per pound of goods (it turns out cheaper!), or try to buy building materials measured in meters and kilograms. Will not work! Not to mention the packaging of goods, where everything is labeled in grams, kilograms and liters, but not in whole numbers, but converted from pounds, ounces, pints and quarts. Milk space in refrigerators is also calculated per half-gallon or gallon, not per liter milk carton.

Do you find it difficult to translate units of measurement from one language to another? Colleagues are ready to help you. Post a question in TCTerms and within a few minutes you will receive an answer.

Calculations for converting units in the converter " Decimal prefix converter" are performed using unitconversion.org functions.

Convert micro to milli:

1. Select the desired category from the list, in in this case"SI prefixes".
2. Enter the value to be converted. Basic arithmetic operations, such as addition (+), subtraction (-), multiplication (*, x), division (/, :, ÷), exponent (^), parentheses and π (pi), are already supported currently.
3. From the list, select the unit of measurement of the value being converted, in this case “micro”.
4. Finally, select the unit of measurement you want the value to be converted to, in this case "milli".
5. After displaying the result of an operation, and whenever appropriate, an option appears to round the result to a certain number of decimal places.

With this calculator, you can enter the value to be converted along with the original measurement unit, for example, "947 micro". In this case, you can use either the full name of the unit of measurement or its abbreviation. After entering the unit of measurement you want to convert, the calculator determines its category, in this case "SI Prefixes". It then converts the entered value into all the appropriate units of measurement that it knows. In the list of results you will undoubtedly find the converted value you need. Alternatively, the value to be converted can be entered as follows: "62 micro to milli", "12 micro -> milli" or "6 micro = milli". In this case, the calculator will also immediately understand into which unit of measurement the original value needs to be converted. Regardless of which of these options is used, the hassle of searching through long selection lists with countless categories and countless supported units is eliminated. All this is done for us by a calculator that copes with its task in a split second.

In addition, the calculator allows you to use mathematical formulas. As a result, not only numbers such as "(58 * 38) micro" are taken into account. You can even use multiple units of measurement directly in the conversion field. For example, such a combination might look like this: “947 micro + 2841 milli” or “5mm x 44cm x 4dm = ? cm^3”. The units of measurement combined in this way must naturally correspond to each other and make sense in a given combination.

If you check the box next to the "Numbers in scientific notation" option, the answer will be represented as an exponential function. For example, 3.526049350629 × 1028. In this form, the representation of the number is divided into an exponent, here 28, and the actual number, here 3.526049350629. In devices that have disabilities display numbers (for example, pocket calculators), the method of writing numbers 3,526 049 350 629 E+28 is also used. In particular, it makes it easier to see very large and very small numbers. If this cell is unchecked, the result is displayed using the usual way recording numbers. In the example above, it would look like this: 35,260,493,506,290,000,000,000,000,000 Regardless of the presentation of the result, the maximum accuracy of this calculator is 14 decimal places. This accuracy should be sufficient for most purposes.

Length and distance converter Mass converter Converter of volume measures of bulk products and food products Area converter Converter of volume and units of measurement in culinary recipes Temperature converter Converter of pressure, mechanical stress, Young's modulus Converter of energy and work Converter of power Converter of force Converter of time Linear speed converter Flat angle Converter thermal efficiency and fuel efficiency Converter of numbers in various number systems Converter of units of measurement of quantity of information Currency rates Women's clothing and shoe sizes Men's clothing and shoe sizes Angular velocity and rotation frequency converter Acceleration converter Angular acceleration converter Density converter Specific volume converter Moment of inertia converter Moment of force converter Torque converter Specific heat of combustion converter (by mass) Energy density and specific heat of combustion converter (by volume) Temperature difference converter Coefficient of thermal expansion converter Thermal resistance converter Thermal conductivity converter Specific heat capacity converter Energy exposure and thermal radiation power converter Heat flux density converter Heat transfer coefficient converter Volume flow rate converter Mass flow rate converter Molar flow rate converter Mass flow density converter Molar concentration converter Mass concentration in solution converter Dynamic (absolute) viscosity converter Kinematic viscosity converter Surface tension converter Vapor permeability converter Vapor permeability and vapor transfer rate converter Sound level converter Microphone sensitivity converter Sound Pressure Level (SPL) Converter Sound Pressure Level Converter with Selectable Reference Pressure Luminance Converter Luminous Intensity Converter Illuminance Converter Computer Graphics Resolution Converter Frequency and Wavelength Converter Diopter Power and Focal Length Diopter Power and Lens Magnification (×) Electric charge converter Linear charge density converter Surface charge density converter Volume charge density converter Electric current converter Linear current density converter Surface current density converter Electric field strength converter Electrostatic potential and voltage converter Electrical resistance converter Electrical resistivity converter Electrical conductivity converter Electrical conductivity converter Electrical capacitance Inductance converter American wire gauge converter Levels in dBm (dBm or dBm), dBV (dBV), watts, etc. units Magnetomotive force converter Magnetic field strength converter Magnetic flux converter Magnetic induction converter Radiation. Ionizing radiation absorbed dose rate converter Radioactivity. Radioactive decay converter Radiation. Exposure dose converter Radiation. Absorbed dose converter Decimal prefix converter Data transfer Typography and image processing unit converter Timber volume unit converter Calculation of molar mass D. I. Mendeleev’s periodic table of chemical elements

1 micro [μ] = 1000 nano [n]

Initial value

Converted value

without prefix yotta zetta exa peta tera giga mega kilo hecto deca deci santi milli micro nano pico femto atto zepto yocto

Metric system and International System of Units (SI)

Introduction

In this article we will talk about the metric system and its history. We will see how and why it began and how it gradually evolved into what we have today. We will also look at the SI system, which was developed from the metric system of measures.

For our ancestors, who lived in a world full of dangers, the ability to measure various quantities in their natural habitat made it possible to get closer to understanding the essence of natural phenomena, knowledge of their environment and the ability to somehow influence what surrounded them. That is why people tried to invent and improve various measurement systems. At the dawn of human development, having a measurement system was no less important than it is now. It was necessary to carry out various measurements when building housing, sewing clothes of different sizes, preparing food and, of course, trade and exchange could not do without measurement! Many believe that the creation and adoption of the International System of SI Units is the most serious achievement not only of science and technology, but also of human development in general.

Early measurement systems

In early measurement and number systems, people used traditional objects to measure and compare. For example, it is believed that the decimal system appeared due to the fact that we have ten fingers and toes. Our hands are always with us - that's why since ancient times people have used (and still use) fingers for counting. Still, we haven't always used the base 10 system for counting, and the metric system is a relatively new invention. Each region developed its own systems of units and, although these systems have much in common, most systems are still so different that converting units of measurement from one system to another has always been a problem. This problem became more and more serious as trade between different peoples developed.

The accuracy of the first systems of weights and measures directly depended on the size of the objects that surrounded the people who developed these systems. It is clear that the measurements were inaccurate, since the “measuring devices” did not have exact dimensions. For example, parts of the body were commonly used as a measure of length; mass and volume were measured using the volume and mass of seeds and other small objects whose dimensions were more or less the same. Below we will take a closer look at such units.

Length measures

In ancient Egypt, length was first measured simply elbows, and later with royal elbows. The length of the elbow was determined as the distance from the bend of the elbow to the end of the extended middle finger. Thus, the royal cubit was defined as the cubit of the reigning pharaoh. A model cubit was created and made available to the general public so that everyone could make their own length measures. This, of course, was an arbitrary unit that changed when a new reigning person took the throne. Ancient Babylon used a similar system, but with minor differences.

The elbow was divided into smaller units: palm, hand, zerets(ft), and you(finger), which were represented by the widths of the palm, hand (with thumb), foot and finger, respectively. At the same time, they decided to agree on how many fingers there were in the palm (4), in the hand (5) and in the elbow (28 in Egypt and 30 in Babylon). It was more convenient and more accurate than measuring ratios every time.

Measures of mass and weight

Weight measures were also based on the parameters of various objects. Seeds, grains, beans and similar items were used as weight measures. A classic example of a unit of mass that is still used today is carat. Nowadays, the weight of precious stones and pearls is measured in carats, and once upon a time the weight of carob seeds, otherwise called carob, was determined as a carat. The tree is cultivated in the Mediterranean, and its seeds are distinguished by their constant mass, so they were convenient to use as a measure of weight and mass. Different places used different seeds as small units of weight, and larger units were usually multiples of smaller units. Archaeologists often find similar large weights, usually made of stone. They consisted of 60, 100 and other numbers of small units. Since there was no uniform standard for the number of small units, as well as for their weight, this led to conflicts when sellers and buyers who lived in different places met.

Volume measures

Initially, volume was also measured using small objects. For example, the volume of a pot or jug ​​was determined by filling it to the top with small objects relative to the standard volume - like seeds. However, the lack of standardization led to the same problems when measuring volume as when measuring mass.

Evolution of various systems of measures

The ancient Greek system of measures was based on the ancient Egyptian and Babylonian ones, and the Romans created their system based on the ancient Greek one. Then, through fire and sword and, of course, through trade, these systems spread throughout Europe. It should be noted that here we are talking only about the most common systems. But there were many other systems of weights and measures, because exchange and trade were necessary for absolutely everyone. If there was no written language in the area or it was not customary to record the results of the exchange, then we can only guess at how these people measured volume and weight.

There are many regional variations in systems of measures and weights. This is due to their independent development and the influence of other systems on them as a result of trade and conquest. There were different systems not only in different countries, but often within the same country, where each trading city had its own, because local rulers did not want unification in order to maintain their power. As travel, trade, industry, and science developed, many countries sought to unify systems of weights and measures, at least within their own countries.

Already in the 13th century, and possibly earlier, scientists and philosophers discussed the creation of a unified measurement system. However, it was only after the French Revolution and the subsequent colonization of various regions of the world by France and other European countries, which already had their own systems of weights and measures, that a new system was developed, adopted in most countries of the world. This new system was decimal metric system. It was based on the base 10, that is, for any physical quantity there was one basic unit, and all other units could be formed in a standard way using decimal prefixes. Each such fractional or multiple unit could be divided into ten smaller units, and these smaller units could in turn be divided into 10 even smaller units, and so on.

As we know, most early measurement systems were not based on base 10. The convenience of a system with base 10 is that the number system we are familiar with has the same base, which allows us to quickly and conveniently, using simple and familiar rules, convert from smaller units to big and vice versa. Many scientists believe that the choice of ten as the base of the number system is arbitrary and is connected only with the fact that we have ten fingers and if we had a different number of fingers, then we would probably use a different number system.

Metric system

In the early days of the metric system, man-made prototypes were used as measures of length and weight, as in previous systems. The metric system has evolved from a system based on material standards and dependence on their accuracy to a system based on natural phenomena and fundamental physical constants. For example, the time unit second was initially defined as a fraction of the tropical year 1900. The disadvantage of this definition was the impossibility of experimental verification of this constant in subsequent years. Therefore, the second was redefined as a certain number of periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the radioactive atom of cesium-133, which is at rest at 0 K. The unit of distance, the meter, was related to the wavelength of the line of the radiation spectrum of the isotope krypton-86, but later The meter was redefined as the distance that light travels in a vacuum in a period of time equal to 1/299,792,458 of a second.

The International System of Units (SI) was created based on the metric system. It should be noted that traditionally the metric system includes units of mass, length and time, but in the SI system the number of base units has been expanded to seven. We will discuss them below.

International System of Units (SI)

The International System of Units (SI) has seven basic units for measuring basic quantities (mass, time, length, luminous intensity, amount of matter, electric current, thermodynamic temperature). This kilogram(kg) to measure mass, second(c) to measure time, meter(m) to measure distance, candela(cd) to measure luminous intensity, mole(abbreviation mole) to measure the amount of a substance, ampere(A) to measure electric current, and kelvin(K) to measure temperature.

Currently, only the kilogram still has a man-made standard, while the remaining units are based on universal physical constants or natural phenomena. This is convenient because the physical constants or natural phenomena on which the units of measurement are based can be easily verified at any time; In addition, there is no danger of loss or damage to standards. There is also no need to create copies of standards to ensure their availability in different parts of the world. This eliminates errors associated with the accuracy of making copies of physical objects, and thus provides greater accuracy.

Decimal prefixes

To form multiples and submultiples that differ from the base units of the SI system by a certain integer number of times, which is a power of ten, it uses prefixes attached to the name of the base unit. The following is a list of all currently used prefixes and the decimal factors they represent:

For example, 5 gigameters is equal to 5,000,000,000 meters, while 3 microcandelas is equal to 0.000003 candelas. It is interesting to note that, despite the presence of a prefix in the unit kilogram, it is the base unit of the SI. Therefore, the above prefixes are applied with the gram as if it were a base unit.

At the time of writing this article, there are only three countries that have not adopted the SI system: the United States, Liberia and Myanmar. In Canada and the UK, traditional units are still widely used, even though the SI system is the official unit system in these countries. It’s enough to go into a store and see price tags per pound of goods (it turns out cheaper!), or try to buy building materials measured in meters and kilograms. Will not work! Not to mention the packaging of goods, where everything is labeled in grams, kilograms and liters, but not in whole numbers, but converted from pounds, ounces, pints and quarts. Milk space in refrigerators is also calculated per half-gallon or gallon, not per liter milk carton.

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Calculations for converting units in the converter " Decimal prefix converter" are performed using unitconversion.org functions.

• 1 General information
• 2 History
• 3 SI units
  • 3.1 Basic units
  • 3.2 Derived units
• 4 Non-SI units
• Consoles

General information

The SI system was adopted by the XI General Conference on Weights and Measures, and some subsequent conferences made a number of changes to the SI.

The SI system defines seven main And derivatives units of measurement, as well as a set of . Standard abbreviations for units of measurement and rules for recording derived units have been established.

In Russia, GOST 8.417-2002 is in force, which prescribes the mandatory use of SI. It lists the units of measurement, gives their Russian and international names and establishes the rules for their use. According to these rules in international documents and only international designations may be used on instrument scales. In internal documents and publications, you can use either international or Russian designations (but not both at the same time).

Basic units: kilogram, meter, second, ampere, kelvin, mole and candela. Within the SI framework, these units are considered to have independent dimensions, that is, none of the basic units can be obtained from the others.

Derived units are obtained from the basic ones using algebraic operations such as multiplication and division. Some of the derived units in the SI System are given their own names.

Consoles can be used before names of units of measurement; they mean that a unit of measurement must be multiplied or divided by a certain integer, a power of 10. For example, the prefix “kilo” means multiplying by 1000 (kilometer = 1000 meters). SI prefixes are also called decimal prefixes.

Story

The SI system is based on the metric system of measures, which was created by French scientists and was first widely adopted after the French Revolution. Before the introduction of the metric system, units of measurement were chosen randomly and independently of each other. Therefore, conversion from one unit of measurement to another was difficult. In addition, they were used in different places different units measurements, sometimes with same names. The metric system was supposed to be convenient and unified system measures and weights.

In 1799, two standards were approved - for the unit of length (meter) and for the unit of weight (kilogram).

In 1874, the GHS system was introduced, based on three units of measurement - centimeter, gram and second. Were also introduced decimal prefixes from micro to mega.

In 1889, the 1st General Conference on Weights and Measures adopted a system of measures similar to the GHS, but based on the meter, kilogram and second, since these units were considered more convenient for practical use.

Subsequently, basic units were introduced for measuring physical quantities in the field of electricity and optics.

In 1960, the XI General Conference on Weights and Measures adopted a standard that was first called the International System of Units (SI).

In 1971, the IV General Conference on Weights and Measures amended the SI, adding, in particular, a unit for measuring the amount of a substance (mole).

SI is now accepted as the legal system of units of measurement by most countries in the world and is almost always used in the scientific field (even in countries that have not adopted SI).

SI units

There is no dot after the designations of SI units and their derivatives, unlike usual abbreviations.

Basic units

Derived units

Derived units can be expressed in terms of base units using the mathematical operations of multiplication and division. Some of the derived units, for convenience, are given their own names; such units can also be used in mathematical expressions to form other derived units.

The mathematical expression for a derived unit of measurement follows from the physical law by which this unit of measurement is defined or the definition of the physical quantity for which it is introduced. For example, speed is the distance a body travels per unit time. Accordingly, the unit of measurement for speed is m/s (meter per second).

Often the same unit of measurement can be written in different ways, using a different set of base and derived units (see, for example, the last column in the table ). However, in practice, established (or simply generally accepted) expressions are used, which the best way reflect physical meaning measured quantity. For example, N×m should be used to write the value of a moment of force, and should not be m×N or J.

Units not included in the SI System

Some units of measurement not included in the SI System are, by decision of the General Conference on Weights and Measures, “allowed for use in conjunction with SI.”