章节大纲

  • 常规

    全部折叠 展开全部

  • 质子

    A bright yellow convertible sports car with distinctive features parked on grass.

    Can you name this car?
    ::你能给这辆车起名吗?

    Describing what we can see is a fairly easy matter.  If we are asked to describe the sports car illustrated below, we could all quickly come up with a fairly accurate description.  A person knowledgeable about cars would include more details, but everyone would have the basic information in their description.
    ::描述我们所看到的是一个相当容易的事情。 如果我们被要求描述下面所描述的体育车,我们就能很快找到一个相当准确的描述。 一个了解汽车的人会包含更多细节,但每个人都会知道这些描述中的基本信息。

    What makes the description easy to come up with? We can see it, we have a common language to describe it (size, color, construction), and we have a basic idea of what it is (a car, not a house or a tree).  Scientists have far more difficulty in describing things they cannot see.  There is no way to look directly at an and see its detailed structure.  When a discovery is first made, there is often no language to use to tell others exactly what it is.  This was the problem in talking about the atom and its structure. 
    ::是什么使得描述容易得出呢?我们可以看到它,我们有一个共同的语言来描述它(大小、颜色、构造),我们对它是什么(汽车、房屋或树)有一个基本的认识。科学家在描述他们看不到的东西方面困难得多。没有办法直接看到和观察它的详细结构。当发现一开始发现时,常常没有语言可以用来告诉别人它到底是什么。这就是谈论原子及其结构的问题。

    Putting the Puzzle Pieces Together
    ::将谜题拼凑在一起

    builds upon itself – one piece connects to another.  Sometimes the puzzle doesn't seem to make sense because some of the pieces are missing at the moment.  Each finding gives a clearer picture of the whole and also raises new questions.  The detective work that led to the discovery of the proton was built upon finding pieces to the puzzle and putting them together in the right way.
    ::发现质子的侦探工作建立在找到解谜的碎片并用正确的方式把它们拼凑在一起的基础上。

    The was discovered using a .  An electric current was passed from the cathode (the negative pole) to the anode (positive pole).  Several experiments showed that particles were emitted at the cathode and that these particles had a negative charge.  These experiments demonstrated the presence of electrons.
    ::电流从阴极(阴极)传到阳极(阳极),若干实验显示阴极释放了微粒,这些微粒有负电荷。这些实验表明存在电子。

    Diagram illustrating a cathode ray tube setup used for electron discovery.
    JJ Thomson's experiment with cathode rays.

    If cathode rays are electrons that are given off by the metal atoms of the cathode, then what remains of the atoms that have lost those electrons? We know several basic things about electrical charges. They are carried by particles of matter. Millikan's showed that they exist as whole-number multiples of a single basic unit. Atoms have no overall electrical charge, meaning that each and every atom contains an exactly equal number of positively and negatively charged particles. A hydrogen atom is the simplest kind of atom with only one electron. When that electron is removed, a positively charged particle should remain.
    ::如果阴极射线是阴极金属原子释放出来的电子,那么失去这些电子的原子的剩余部分是什么? 我们知道一些关于电荷的基本内容。 它们是由物质粒子携带的。 Millikan的显示它们存在于一个基本单元的完整数字倍数中。原子没有总电荷,这意味着每个原子都含有完全相等数量的正负电荷粒子。氢原子是最简单的原子,只有一种电子。当电子被移除时,正电荷粒子应该保留下来。

    Discovery of the Proton
    ::发现质子

    In 1886, Eugene Goldstein (1850-1930) discovered evidence for the existence of this positively charged particle. Using a cathode ray tube with holes in the cathode, he noticed that there were rays traveling in the opposite direction from the cathode rays. He called these canal rays and showed that they were composed of positively charged particles. The proton is the positively charged subatomic particle present in all atoms. The mass of the proton is about 1840 times the mass of the electron.
    ::1886年,Eugene Goldstein(1850-1930年)发现了关于存在这种正电荷粒子的证据。他用阴极内有孔的阴极射线管注意到有射线从阴极射线线向相反方向穿行。他调用这些运河射线,表明这些射线由正电荷粒子组成。质子是所有原子中存在的正电荷亚原子粒子。质子的质量大约是电子质量的1840倍。

    Summary
    ::摘要

    • When an electron is removed from a hydrogen atom, a proton remains.
      ::当从氢原子中移除电子时,质子将留下。
    • Goldstein observed rays travelling in the opposite direction of the cathode rays in a cathode ray tube.
      ::Goldstein观测到阴极射线管阴极射线向相反方向穿行的射线。
    • He demonstrated that these rays were positive particles and called the canal rays.
      ::他证明这些射线是正微粒,称为运河射线。

    Review
    ::回顾

    1. Why is it easy to describe things we can see?
      ::为什么很容易描述我们所看到的事物?
    2. Why did researchers believe that the particle left after electrons were emitted as cathode rays had to be positive?
      ::为什么研究人员认为电子排放后留下的粒子是阴极射线必须呈阳性?
    3. Atoms, which are always neutral in electric charge, contain electrons as well as protons and neutrons. An electron has an electrical charge of -1. If an atom has three electrons, infer how many protons it has.
      ::原子在电荷中总是中性,含有电子以及质子和中子,电子的电荷为 -1. 如果原子有三个电子,则可以推断它有多少质子。
    4. How many electrons does it take to weigh the same as one proton?
      ::一个质子的重量需要多少个电子?