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  • General

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  • 物理属性

    A crowd observes a brightly colored drag racing car parked on a city street.

    Why are drag car standards constantly reinforced?
    ::为什么不断加强拖车标准?

    Drag racing is a highly competitive (and expensive) sport. There are a variety of classes of vehicles, ranging from stock classes (depending on car weight , engine size, and degree of engine modification) all the way up to the Top Fuel class with weights of over two thousand pounds and capable of top speeds of well over 300 miles per hour at the end of the quarter-mile. The standards for each class are well defined and frequent checks are made of engine dimensions and components to ensure that the rules are followed.
    ::拖拉赛是一项竞争激烈( 且昂贵) 的运动。 各种车辆种类繁多, 从库存等级( 取决于车重量、 引擎大小和引擎改装程度)一直到重量超过 2,000 磅的顶级燃料级, 在四分之一英里的末端, 最高速度超过每小时300 英里。 每个等级的标准都有明确规定, 并经常对引擎尺寸和部件进行检查, 以确保遵守规则 。

    Physical Properties
    ::物理属性

    A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Silver is a shiny metal that conducts electricity very well. It can be molded into thin sheets, a property called malleability. Salt is dull and brittle and conducts electricity when it has been dissolved into water, which it does quite easily. include color, hardness, malleability, , electrical conductivity, density, points , and boiling points .
    ::物质财产是一种物质的特点,可以在不改变物质特性的情况下加以观察或测量,银是一种闪亮的金属,能很好地进行电力生产,可被仿制成薄薄的板块,一种称为易腐性的财产,盐是枯燥和易碎的,在溶入水中时进行电力,它很容易做到。 包括颜色、硬度、易腐性、易碎性、电导性、密度、点和沸点。

    For the , color does not vary much from one element to the next. The vast majority of elements are colorless, silver, or gray. Some elements do have distinctive colors: sulfur and chlorine are yellow, copper is (of course) copper-colored, and elemental bromine is red.
    ::对于此元素,颜色各元素之间差别不大。绝大多数元素是无色、无银或灰色的。有些元素有不同的颜色:硫和氯是黄色的,铜(当然)是铜色的,元素溴是红色的。

    Density can be a very useful parameter for identifying an element. Of the materials that exist as solids at room temperature , iodine has a very low density compared to zinc, chromium, and tin. Gold has a very high density, as does platinum.
    ::密度可以成为确定元素的一个非常有用的参数。 在室温时作为固体存在的材料中,碘与锌、铬和锡相比密度非常低。 黄金和白金一样密度很高。

    Hardness helps determine how an element (especially a metal) might be used. Many elements are fairly soft (silver and gold, for example) while others (such as titanium, tungsten, and chromium) are much harder. Carbon is an interesting example of hardness. In graphite (the “lead” found in pencils) the carbon is very soft, while the carbon in a diamond is roughly seven times as hard.
    ::硬度有助于确定元素( 特别是金属 ) 如何使用。 许多元素相当柔软( 软和金, 例如) , 而其他元素( 如钛、 钨和铬) 则更难使用 。 碳是硬性的有趣例子。 在石墨( 在铅笔中找到的“ 铅 ” ) 中, 碳非常软, 而钻石中的碳大约是硬的七倍。

    A close-up of a yellow pencil's tip resting on a red surface.
    Pencil.
    A gold ring with a round diamond, showcasing physical properties of metals and gemstones.
    Diamond ring.

    Melting and boiling points are somewhat unique identifiers, especially of compounds. In addition to giving some idea as to the identity of the , important information can be obtained about the purity of the material.
    ::熔点和沸点是某些独特的识别资料,特别是化合物的识别资料,除了对材料的身份有所了解外,还可以获得关于材料纯度的重要信息。

     

     

     

     

    Is That Really Gold? Archimedes and Density
    ::那真的是黄金吗?

    How do you determine the density of an irregularly shaped object? Learn how Archimedes did this thousands of years ago with just a beaker, water, and some simple math. 
    ::如何确定一个非正常形状物体的密度 ? 亚基米德如何在几千年前用一个烧水、水和一些简单的数学 来完成这一任务 。

      

     

     

    Summary
    ::摘要

    • A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance.
      ::有形财产是一种物质的特点,可以在不改变物质特性的情况下加以观察或测量。
    • Physical properties include color, density, hardness, and melting and boiling points.
      ::物理特性包括颜色、密度、硬度、熔点和沸点。

    Review
    ::回顾

    1. What is a physical property?
      ::什么是物质财产?
    2. What color are most metals?
      ::大多数金属是什么颜色?
    3. Is titanium harder or softer than gold?
      ::钛比金子硬还是软?