章节大纲

  • 常规

    全部折叠 展开全部

  • 波波干涉

    Raindrops creating ripples in a blue water surface, illustrating wave interference.

    When raindrops fall into still water, they create tiny waves that spread out in all directions away from the drops. What happens when the waves from two different raindrops meet? They interfere with each other.
    ::当雨滴落到静水中时,雨滴会形成微小的波浪,从水滴的四面八方涌出。当两个不同的雨滴的波浪相遇的时候,会怎样呢?它们互相干扰。

    When Waves Meet
    ::波浪相遇时

    When two or more waves meet, they interact with each other. The interaction of waves with other waves is called wave interference . Wave interference may occur when two waves that are traveling in opposite directions meet. The two waves pass through each other, and this affects their amplitude . Amplitude is the maximum the particles of the medium move from their resting positions when a wave passes through. How amplitude is affected by wave interference depends on the type of interference. Interference can be constructive or destructive.
    ::当两个或两个以上的海浪相撞时,它们彼此互动。波与其他波的相互作用被称为波干扰。波的干扰可能发生在两个波相撞时。两波相撞时,波的干扰可能会发生,这影响到它们的振幅。振幅是波经过时中程距离休息位置的最大粒子。波的干扰对振幅的影响取决于干扰的类型。干涉可以是建设性的,也可以是破坏性的。

    Constructive Interference
    ::建设性的干涉

    Constructive interference occurs when the crests, or highest points, of one wave overlap the crests of the other wave. You can see this in the Figure . As the waves pass through each other, the crests combine to produce a wave with greater amplitude. 
    ::当一波的顶峰或最高点与另一波的顶峰重合时,就会发生建设性干扰。您可以从图中看到这一点。随着波浪的相互穿透,顶峰会合在一起产生振幅更大的波。

    Constructive interference of waves with overlapping crests and increased amplitude.

    Destructive Interference
    ::破坏性干扰

    Destructive interference occurs when the crests of one wave overlap the troughs, or lowest points, of another wave. The Figure shows what happens. As the waves pass through each other, the crests and troughs cancel each other out to produce a wave with zero amplitude. 
    ::当一波的顶峰与另一波的底部或最低点相重叠时,就会发生破坏性干扰。图中显示了发生的情况。随着波相互穿透,顶部和底部相互勾销,产生零振幅的波。

    Visualization of destructive interference showing overlapping wave crests and troughs resulting in zero amplitude.

    In shallow ponds, the depth of the water influences the . Use the Stow Lake simulation below to make waves of different speeds. These will display different interference patterns. Try pausing the simulation to analyze the wave in the graph and find a spot where the wave pattern is maximized and where it is zero to learn more about wave interference:
    ::在浅水池中,水的深度会影响 。 使用下面的斯托湖模拟来制造不同速度的波。 这将显示不同的干扰模式。 尝试用模拟来分析图表中的波, 并找到一个波模式最大化和了解波干扰更多情况为零的地方 :

    Standing Waves
    ::常态波浪

    Waves may reflect off an obstacle that they are unable to pass through. When waves are reflected straight back from an obstacle, the reflected waves interfere with the original waves and create standing waves . These are waves that appear to be standing still. Standing waves occur because of a combination of constructive and destructive interference. 
    ::波浪可能反射出它们无法穿越的障碍。 当波浪从一个障碍直接反射回来时,反射波会干扰最初的波浪,并造成起伏波。 这些波浪似乎站立不动。 常态波浪会因建设性和破坏性干扰的结合而出现。

    Q : How could you use a rope to produce standing waves?
    ::问:你怎么能用绳子来制造起立波浪呢?

    A : You could tie one end of the rope to a fixed object, such as doorknob, and move the other end up and down to generate waves in the rope. When the waves reach the fixed object, they are reflected back. The original waves and the reflected waves interfere to produce a standing wave . Try it yourself and see if the waves appear to stand still. 
    ::A:你可以将绳子的一端绑在门把手等固定物体上,然后将另一端上下移动,在绳子上产生波浪。当波浪到达固定物体时,它们会反射回来。最初的波浪和反射波会干扰形成一个立波。你试试看波浪是否保持静止。

    Have you ever done “the wave” at a sporting event? Well, then you have helped to create a wave. Learn more about waves and wave interference by launching the Stadium Wave simulation below:
    ::你曾经在体育赛事上做过“波”吗? 那么,你帮助制造了波。 通过在下面启动体育场波模拟,更多了解波和波的干扰:

    Further Reading
    ::继续阅读

    • Beat Frequencies
      ::Beabe 分数
    • Standing Waves
      ::常态波浪

    Summary
    ::摘要

    • Wave interference is the interaction of waves with other waves.
      ::波的干扰是波与其他波的相互作用。
    • Constructive interference occurs when the crests of one wave overlap the crests of the other wave, causing an increase in wave amplitude.
      ::当一波的顶峰与另一波的顶峰重合时,就会发生建设性干扰,导致波的振幅上升。
    • Destructive interference occurs when the crests of one wave overlap the troughs of the other wave, causing a decrease in wave amplitude.
      ::当一波的顶峰与另一波的底部重合时,就会发生破坏性干扰,导致波的振幅下降。
    • When waves are reflected straight back from an obstacle, the reflected waves interfere with the original waves and create standing waves.
      ::当波浪从障碍物直接反射回来时, 反射波干扰了最初的波浪, 并造成起伏波浪。

    Review
    ::回顾

    1. What is wave interference?
      ::什么是波干扰?
    2. Create a table comparing and contrasting constructive and destructive interference.
      ::建立一个比较和对比建设性和破坏性干扰的表格。
    3. What are standing waves? How do they form?
      ::什么是常态海浪,它们是如何形成的?