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The centimeter is a unit of length equal to one hundredth of a meter; the English symbol is abbreviated to: cm., 1 centimeter =1/100
meter
. 1cm (cm) =10mm (cm)
millimeter
) =0.1dm (
decimetre
) =0.01m (m).
International System of Units
Seven independent quantities were chosen as basic quantities, the first being length. Its basic unit name is the meter, the symbol is m, and the centimeter is not the SI unit.
- Chinese name
- centimetre
- Foreign name
- centimeter [4]
- alias
- centimetre
- subject
- Mathematical science
- glyphsign
- cm
- nature
- International System of Units
- Generic type
- Mathematical terms
Centimeter, a unit of length, abbreviated (symbol) : cm.
Conversion of units relating to centimeters: 1 centimeter =10 millimeters =10000
micron
= 10000000
nanometer
= 0.1
decimetre
=0.01 m =0.00001
kilometre
(Ps: cm commonly known
centimetre
.)
A unit of length is a measurement
Spatial distance
The basic unit is the basic unit developed by human beings in order to regulate the length. Its international unit is"
meter
(symbol "m"), commonly used units are
millimeter
(mm),
centimetre
(cm),
decimetre
(dm),
kilometre
(km), meter (m), micron (μm), nanometer (nm) and so on. Units of length play an important role in various fields.
Geometric measurement, also known as length measurement, is a science with early start, rapid development and mature technology in our country. China is a famous ancient civilization, with a brilliant ancient civilization, measurement and testing technology is an important part of this civilization, and as a metrology of geometric measurement has a long history of development. As early as the Shang Dynasty, China began to have ivory ruler, Qin Shi Huang unified the system of weights and measures, there has been the germination of interchangeability, which has been confirmed from the eighth wonder of the world Terra Cotta Warriors unearthed arrow crossbow machine. Around 1600 AD, China began to develop length and timing measurement. The basic unit of length measurement, that is, geometric measurement, is the meter.
A unit of measurement is a scale chosen to measure a certain type of measurable size, and its magnitude is determined by the definition of the unit. The physical standard that embodies the given quantity value of the unit definition and has the highest accuracy is called the measurement basis of the unit.
[1]
1, make students initially understand the length unit centimeter, initially establish the concept of 1 centimeter length;
2, so that students initially learn to use the scale to measure the length of the object method (limited to the whole centimeter), learn to use the ruler to draw a fixed length (whole centimeter) line segment.
3. Cultivate students' hands-on ability and strengthen students' expression and communication ability.
Focus: Enable students to establish a 1 cm length concept.
Difficulty: Drawing a fixed length line segment.
1. Review old knowledge
Teaching process
The team leader shows the results, and the members answer why ② and ④ are line segments? Another group of students answered why are ①, ③, ⑤ not line segments?
2. Lead the conversation
Teacher: Each of us has five fingers on each hand. Do you want to know how long each finger is?
Student: Yes.
Teacher: If we want to know the length of a finger, we can measure it with a meter stick. (Show the meter stick)
To measure the length of an object, we must first understand the unit of length on the meter rule. Today, we will study the smaller unit of length "centimeter" (blackboard: centimeter). Shorter things can be measured in centimetres.
(Comment and analysis: Starting from the review of old knowledge, the use of group cooperative learning, to attract students to take the initiative to participate in learning activities, encourage students to observe and judge, closely related to the actual life of students to reveal the meaning of "centimeter", not only the necessary psychological preparation for learning new knowledge, but also further stimulate the desire of students to learn new knowledge.)
[2]
Is the centimeter an international unit? Chen Liqi discussed this topic with his peers in the teaching process, because the middle school physics teachers had no information about it in the middle school physics textbooks and the university general physics textbooks
International System of Units
Systematic introduction of knowledge, so the answer to this question is very different. Some of my colleagues believe that the centimeter is not an international unit because that is what they were taught when they were studying in high school or university, which makes me more eager to know so as to avoid misinformation. Chen Liqi consulted the relevant information and sorted out the following text for reference only.
(1)
SI basic unit
Seven. That is, the length unit meter, the mass unit kilogram, the time unit second, the current unit ampere, the thermodynamic temperature unit Kelvin, the amount of matter unit mole, and the luminous intensity unit Candela.
(2) 2 auxiliary units of SI system. That is, plane Angle unit radian, solid Angle unit sphericity.
It can be seen that the International System of Units chooses seven independent quantities as basic quantities, the first of which is length. Its basic unit name is the meter and its symbol is m. The meter is the SI basic unit name of length, the unit of length, width, thickness, radius, circumference, distance and other physical quantities, are expressed in the meter or its decimal multiple units. The centimeter is not an international unit.
[3]
