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  • 理论

    A baseball batter in a blue uniform stands ready to hit, with a crowd in the background.

     

    Do you have a theory about why this batter can't hit?
    ::你对这个打手打不中的原因有理论吗?

    This batter hasn't hit a ball in his last 20 at bats. His coach has a theory: it's because he needs glasses. The idea is a good one, although it is not a theory. In common speech, the word theory is often misused. It is often misused when referring to scientific ideas as well. What would be a better word to use?
    ::这个击球手在过去20年没有打过球。他的教练有一个理论: 因为他需要眼镜。 这个想法是好的, 虽然不是一个理论。 在普通的演讲中,这个理论经常被滥用。 当他提到科学思想时,它也经常被滥用。 什么是更好的用词呢?

    Theory
    ::理论理论

    Scientists collect evidence to test a  hypothesis . The evidence may refute the hypothesis. In that case, it will be thrown out. The evidence may support the hypothesis. The scientists will then gather more evidence. The scientists will accept the hypothesis if: (1) There is no significant evidence to refute the hypothesis. (2) There is an enormous amount of evidence to support the hypothesis. The hypothesis may then become a theory.
    ::科学家收集证据以检验假设。证据可以反驳假设。在这种情况下,证据将被抛出。证据可以支持假设。然后科学家将收集更多的证据。如果sad1) 没有重要证据来反驳假设,科学家将接受假设。(2) 有大量证据支持假设。然后,假设可能变成理论。

    A scientific  theory  is supported by many types of evidence. It is a synthesis of evidence from many  experiments  and observations. A theory has no major inconsistencies. A theory is a simple  model  of reality. It is simpler than the phenomenon itself. A theory explains a phenomenon. Scientists can use a theory to make predictions.
    ::科学理论得到许多类型的证据的支持。 它是来自许多实验和观察的证据的合成。 理论没有重大不一致之处。 理论是一个简单的现实模型。 它比现象本身简单。 理论解释一种现象。 科学家可以使用理论作出预测。

    A theory is constantly tested. If some  data  does not agree with the theory, the theory can be revised. If the theory cannot match the data, it is thrown out. That being said, sometimes a theory is well-established; it has a lot of evidence to back it up. A well-established theory is unlikely to be overthrown. It may just need to be modified a bit. But  science  does not prove anything beyond a  shadow  of a doubt.
    ::一个理论不断被测试。如果某些数据与理论不一致,则该理论可以修改。如果该理论无法与数据匹配,就会被丢弃。说到此,有时一个理论已经确立;它有许多证据可以支持它。一个既定的理论不太可能被推翻。它可能只需要稍作修改。但科学不能证明什么是不容置疑的。

    Three Essential Theories
    ::三个基本理论

    The three theories below are essential in Earth science. Each accounts for an enormous amount of data. Each is supported by many lines of evidence. All can be used to make predications. As new evidence arises, any of these theories may need to be altered. But none of these three are likely ever to be disproved. They are accepted by nearly all of the credible scientists in their fields.
    ::以下三条理论对地球科学至关重要。 每种理论都包含大量数据。 每条数据都有许多证据支持。 所有这些都可以用来作出预言。 随着新的证据的出现, 任何一条理论都可能需要改变。 但这三个理论中没有一个可能永远无法被反驳。 它们几乎都为各自领域的可靠科学家所接受。

    The Theory of Evolution
    ::进进理论理论理论

    Evolution means change over time. Darwin’s theory of  evolution  says that organisms change over time ( Figure   ). Evolution is seen in the  fossil  record. It is seen in the way organisms develop. Evolution is evident in the geographic locations where organism are found. It is evident in the  genes  of living organisms. Evolution has a  mechanism  called  natural selection . The organism that is best suited to its environment is most likely to survive. 
    ::达尔文的进化理论指出生物随时间变化(图 ) 。 进化在化石记录中可以看到。进化从生物的发展方式中可以看到。进化在发现生物的地理位置中显而易见。进化在生物的基因中显而易见。进化有一个称为自然选择的机制。最适合其环境的有机体最有可能生存下来。

    Graphic depicting the theory of evolution and natural selection processes.

     

    The theory of evolution maintains that modern humans evolved from ape-like ancestors.
    ::进化理论认为,现代人类从类人猿的祖先演变而来。

    The Theory of Plate Tectonics
    ::热板构造理论理论

    Plate tectonics  theory says that slabs of continents move around on Earth's surface. The mechanism for that movement is  seafloor spreading . Plate tectonics explain many things about Earth: (1) geological activity, why it happens where it does; (2)  natural resources , why many are found where they are; and (3) the past and future, what happened in the past and what will happen in the future. The   will be explored in the chapter  Plate Tectonics .
    ::板块构造学理论指出,大陆的板块在地球表面移动。这种移动的机制是海底的扩张。 板块构造学解释了关于地球的许多事情sad1) 地质活动,为什么它发生在哪里;(2) 自然资源,为什么发现很多资源;(3) 过去和未来,过去和将来发生的事情,以及未来会发生什么。这将在板块构造学章中加以探讨。

    The Theory of Climate Change
    ::气候变化理论理论

    The theory of  climate  change is very new. In  fact , scientists don't even call it a theory. But it meets the requirements. These are the things we know: (1) average global temperatures are rising, (2)  greenhouse gases  trap  heat  in the  atmosphere , (3) CO 2  is released into the atmosphere when  fossil fuels  are burned, (4) CO 2  is a greenhouse gas, (5) more CO 2  in the atmosphere traps more heat so global   is rising. No information contradicts this theory, although some details have not been worked out. The theory is very effective at predicting future events, which are already taking place. This idea will be explored in detail in the chapter  Atmospheric Processes .
    ::气候变化理论非常新颖。 事实上,科学家甚至不称它为理论。 但是它满足了要求。 这就是我们所知道的sad1) 全球平均气温正在上升,(2) 大气中温室气体陷阱热,(3) 化石燃料燃烧时二氧化碳释放到大气中,(4) 二氧化碳是一种温室气体,(5) 大气中更多的二氧化碳捕捉,因此全球温度正在上升。没有任何信息与这一理论相矛盾,尽管一些细节尚未确定。 理论在预测已经发生的未来事件方面非常有效。 这个想法将在大气过程一章中详细探讨。

    Laws
    ::法律 法律 法律

    Many people think that any idea that is completely accepted in science is a  law . But that is not true. In science, a  law  is something that always applies under the same conditions. A law explains a fairly simple phenomenon. A theory is much more complex: it tells you why something happens. A law only tells you that it happens. For example, if you hold something above the ground and let go, it will fall. This phenomenon is recognized by the law of gravity ( Figure   ). Some people say that evolution is "just a theory." But for a complex explanation like evolution, theory is the right word.
    ::许多人认为,科学中完全接受的任何思想都是法律,但事实并非如此。在科学中,法律总是在相同条件下适用。法律解释一个相当简单的现象。一个理论更复杂得多:它告诉你发生的事情。一个法律只告诉你发生的事情。例如,如果你在地面上持有某种东西而放手,它就会掉下来。这个现象得到重力法的承认(图表 )。有些人说,进化是一个“理论 ” 。但对于像进化这样的复杂解释来说,理论是正确的词。

    Skydivers free-falling together against a cloudy sky, illustrating the law of gravity.

     

    Skydiving is possible because of the law of gravity.
    ::由于重力定律 潜水是可能的

    Summary
    ::摘要

    • A theory is an explanation of a complex phenomenon. A theory tells why something happens.
      ::理论是解释一个复杂的现象。理论说明了为什么会发生一些事情。
    • A theory can be used to predict future events.
      ::可用于预测未来事件的理论。
    • A law describes something that always happens under the same set of circumstances. A law does not say why it happens. But even laws do not always hold.
      ::法律描述了在相同情况下总是发生的事情,法律没有说明为什么会发生,但甚至法律也并不总是站得住脚的。

    Review
    ::回顾

    1. Compare and contrast hypothesis, theory, and law.
      ::比较和对比假设、理论和法律。
    1. Can a hypothesis become a theory?
      ::假设能成为理论吗?
    1. Which of these, if any, is most important in science: hypothesis, theory, or law?
      ::其中哪一个在科学中最重要:假设、理论或法律?

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

    1. What is a scientific theory?
      ::什么是科学理论?
    1. What can be done with a theory?
      ::一个理论能做什么呢?
    1. What is a law?
      ::什么是法律?
    1. Why is the phrase "only a theory" misleading?
      ::为什么“只是一个理论”这一短语会误导人?