1795, France defined gram as equal to "the absolute weight of a cube with a side length of one hundredth meter and a capacity equal to the melting temperature of water and ice". Because the mass involved in business is far more than one gram, and the quality based on water is inconvenient and unstable, it is necessary to manufacture a materialized instrument for the definition of quality water in business regulations. Therefore, people made a temporary quality standard: a metal artifact, its mass is g-kg 1000 times.
Second, the relationship between grams and kilograms
"Kilogram" and "gram" are legal units of mass in China. The kilogram can be represented by the letter "kg" and the gram can be represented by the letter "g". Lighter items, such as gold and Chinese herbal medicines, are often used as units. Heavier items, such as watermelons and whole bags of rice, are usually measured in kilograms.
The relationship between grams and kilograms is 1 kg = 1000 grams. Kilogram is the basic unit to measure quality in the international system of units, and it is also one of the most commonly used basic units in daily life. One kilogram is defined as Planck constant 6.626070 15× 10? The mass unit of J. S.
The kilogram is the only basic unit prefixed by the international system of units. 2018 165438+1October16 the 26th international metrology conference adopted the resolution of "revising the international system of units", which formally updated the definition of "kilogram" including international standard quality units. The new international system of units came into effect on May 20, 20 19, World Metrology Day.
Third, the understanding of grams and kilograms
(1) grams and kilograms are units of weight, which both represent the mass of an object. Every object has weight, and weight is widely used in life. For example, if you go to the supermarket to buy things, some items need to be weighed and sold. In this case, grams and kilograms will be used to calculate the value. Grams and kilograms are commonly used in supermarkets, and Jin and two are the most commonly used weight units in the general market.
② There is a conversion between grams and kilograms. There is a conversion relationship between grams and kilograms, and 1000 grams is equal to 1 kilogram. The conversion relationship between grams and kilograms is actually summed up in one sentence as the relationship between three 000. Three zeros need to be removed when converting grams into kilograms, and three zeros need to be added when converting kilograms into grams. By the way, there is a conversion relationship between kilograms and kilograms. 1 1 kg equals 2 kg.
(3) the use of grams and kilograms. The use of grams and kilograms can be distinguished from two dimensions. First, most of the more expensive ones are in grams, such as gold and diamonds. Cheap is mainly kilograms, such as potatoes, corn and other crops, all kilograms. The root cause of this situation may be related to errors. After all, things are expensive, and it is easy to make mistakes if you use a large unit. The second is the quantity of things. If there are many things, it must be in kilograms, so it will be easier to count, but there are fewer things. Generally speaking, for the sake of accuracy, grams are used as units.