1m= 10dm， 1dm= 10cm， 1cm= 10mm
(1) meter
The unit of length "meter" in the international system of units originated in France. 1790 In May, a special committee composed of French scientists suggested that one fortieth of the total length of the earth meridian passing through Paris should be used as the unit of length-meter, and 179 1 year was approved by the French Parliament.
In order to make a benchmark to represent the value of rice, under the leadership of French astronomers Gerliangbule and Mishin, measurements were made from Dunkirk, France to Barcelona, Spain, and from 1792 to 1799.
1799, according to the measurement results, a platinum rice bar with a short section of 3.5mm× 25mm was made, and the distance between the two ends of the bar was set as 1m, which was kept by the French archives, so it was also called "archival rice". This is the earliest definition of rice.
(2) decimeter
Decimeter or dm is one of the metric units of length, and 1 decimeter is equivalent to one tenth of 1 meter. The common conversion relationship is as follows: 1 decimeter = 0.000 1 kilometer (km) = 0. 1 meter (m) = 10 centimeter (cm) = 100 millimeter (mm).
3) cm
Centimeter, unit of length; Chinese: centimeter (s), abbreviated as cm. The unit conversion of centimeters is as follows:1cm =10 mm = 0.1decimeter = 0.0 1 m = 0.0000 1 km.
4) mm
Millimeter, also known as millimeter (or millimeter), is a unit of length and rainfall, and the symbol is ㎜. 1mm is equivalent to one thousandth of 1mm (this means "milli"). The decimal relation is as follows:1mm = 0.1cm = 0.01decimeter = 0.001m = 0.000001km.
Extended data:
Other length units:
(1) km
Kilometer, also known as kilometer, is a unit of length, abbreviated as "km", which is usually used to measure the distance between two places. The common conversion relationship is as follows: 1 km (km) = 1 0,000m (m) = 1 00,000m (cm) =10,000mm (mm); 1.6 1 km = 1 mile.
② Micron
Micron is a unit of length, and the symbol [micron] is pronounced [miú]. 1 micron is equivalent to one millionth of 1 meter (which means "micro"). The conversion relationship is as follows: 1 micron (micron) = 1 000 nanometer (nanometer) = 0.00 1 millimeter (millimeter) = 0.000 1 cm.
(3) Nanometer
Nanometer (symbol is nm) is the unit of length, originally called nanometer, that is, 10-9 meters (65438+ billionth of a meter). Like centimeters, decimeters and meters, it is a unit of measurement for length. It is four times the size of an atom and less than the length of a single bacterium.
A single bacterial microorganism is invisible to the naked eye, and the diameter measured by a microscope is about five microns, which is five thousand nanometers. For example, suppose that the diameter of a hair is 0.05 mm, and it is cut into 50,000 pieces on average in the radial direction, and the thickness of each piece is about one nanometer. That is to say, one nanometer is about 0.000001mm. Nanoscience and technology, sometimes called nanotechnology, is to study the properties and applications of materials with structural dimensions ranging from 1 to 100 nm.
(4) Pimi (pm)
Pimi or pm is the unit of length, and 1 pimi is equivalent to one trillion of 1 meter. Sometimes it is called a micron in atomic physics. The conversion relationship is as follows: 1 picometer =10-12m = 0.001nanometer (nm) = 0.0000 1 micron (micron).
References:
Length unit Baidu Encyclopedia