3.2 计量前缀
Section outline
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What do Latin and Greek have to do with modern science?
::拉丁和希腊与现代科学有什么关系?Isn’t it hard enough to learn English terms? For hundreds of years, the languages of the educated class were Latin and Greek. In part, because the literature of philosophy was Latin and Greek. Even the medieval Bibles were written in those two languages – the first English translation was in the late 1380s. Using Latin and Greek allowed scholars from different countries to communicate more easily with one another. Today we still see many Latin phrases in legal communications (“pro bono” meaning to do something “for the good” and not charge legal fees), scientific naming of biological species, and Latin is used for the annual student speech at Harvard University graduations. Not bad for a “dead” language.
::学习英语术语难道还不够困难吗? 数百年来,受过教育的班级语言是拉丁语和希腊语。 部分因为哲学文学是拉丁语和希腊语。 即使是中世纪圣经也是用这两种语言写的 — — 第一批英文译文是在1380年代末。 使用拉丁语和希腊语让不同国家的学者更容易地相互沟通。 今天,在法律交流中,我们仍看到许多拉丁语(“公益”意指做“为好”而不是收取法律费用 ) , 生物物种的科学命名和拉丁语被用于哈佛大学年度学生毕业演讲。 对“死”语来说,并不坏。Metric Prefixes
::中度前缀Conversions between metric system units are straightforward because the system is based on powers of ten. For example, meters, centimeters, and millimeters are all metric units of length. There are 10 millimeters in 1 centimeter and 100 centimeters in 1 meter. Metric prefixes are used to distinguish between units of different size. These prefixes all derive from either Latin or Greek terms. For example, mega comes from the Greek word , meaning “great”
::公制系统单位之间的转换是直截了当的,因为系统基于10的功率。例如,米、厘米和毫米都是长度的公分单位。1厘米有10毫米,1米有100厘米。用米前缀区分大小不同的单位。这些前缀都来自拉丁语或希腊语。例如,兆字来自希腊语 ,意思是“伟大的”Table lists the most common metric prefixes and their relationship to the central unit that has no prefix. Length is used as an example to demonstrate the relative size of each prefixed unit.
::表格列出了最常见的指标前缀及其与没有前缀的中央单位的关系。以长度为例,说明每个前缀单位的相对大小。SI Prefixes Prefix Unit Abbrev. Meaning Example giga G 1,000,000,000 1 gigameter (Gm) = 10 9 m mega M 1,000,000 1 megameter (Mm) = 10 6 m kilo k 1000 1 kilometer (km) = 1000 m hecto h 100 1 hectometer (hm) = 100 m deka da 10 1 dekameter (dam) = 10 m 1 1 meter (m) deci d 1/10 1 decimeter (dm) = 0.1 m centi c 1/100 1 centimeter (cm) = 0.01 m milli m 1/1000 1 millimeter (mm) = 0.001 m micro μ 1/1,000,000 1 micrometer (μm) = 10 -6 m nano n 1/1,000,000,000 1 nanometer (nm) = 10 -9 m pico p 1/1,000,000,000,000 1 picometer (pm) = 10 -12 m There are more prefixes - some of them rarely used. Have you ever heard of a zeptometer?
::还有更多的前缀- 其中一些很少使用。 你听说过气压计吗 ?There are a couple of odd little practices with the use of metric abbreviations. Most abbreviations are lower-case. We use “m” for meter and not “M”. However, when it comes to volume , the unit “liter” is abbreviated as “L” and not “l”. So we would write 3.5 milliliters as 3.5 mL.
::使用通用缩略语有几种奇特的小做法,大多数缩略语为小写字母。我们用“m”而不是“M”。然而,在体积方面,“liter”单位缩写为“L”而不是“l”。因此,我们写3.5毫升为3.5毫升。As a practical matter, whenever possible you should express the units in a small and manageable number. If you are discussing a material with a mass of 6.5 kg, this is easier than saying it has a mass of 6500 g or 650 dag. All three are correct, but the kg units in this case make for a small and easily managed number. However, if a specific problem needs grams instead of kilograms, go with the grams for consistency.
::实际上,只要有可能,你应该用一个小的、可管理的数字表示单位。如果讨论质量为6.5公斤的材料,这比说质量为6500克或650 dag要容易。所有三个质量都是正确的,但这里的公斤单位可以使用一个小的、易于管理的数字。但是,如果具体的问题需要克而不是公斤,则用克来表示一致性。Practice using metric prefixes with this simulation:
::使用此模拟的度量前缀练习 :Summary
::摘要-
Metric prefixes derive from Latin or Greek terms.
::计量前缀来自拉丁语或希腊语。 -
The prefixes are used to make the units manageable.
::使用前缀使单位可以控制。
Review
::回顾-
What is the prefix for “thousand”?
::“千人”的前缀是什么? -
What is the prefix for 0.01?
::0.01的前缀是什么? -
How would you write 500 milliliters?
::你怎么写500毫升? -
How many decimeters in one meter?
::一米内有多少十分? -
You have a mass that weighs 1.2 hectograms. How many grams does it weigh?
::你有重1.2公斤的重量,重多少克?
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Metric prefixes derive from Latin or Greek terms.