章节大纲

  • Lesson Objective
    ::经验教训目标

    • Explain that mixtures of solids can be separated based on observable properties of their parts such as particle size, shape, color, and magnetic attraction. 
      ::解释固体混合物可以根据其部分的可见特性,如颗粒大小、形状、颜色和磁吸引等进行分离。

    Lesson Vocabulary
    ::词汇表课程

    • dissolve
      ::溶解
    • mixture
      ::混合混合物
    • solution
      ::解决方案

    Introduction
    ::导言

    Oh no! Your younger sister just mixed up all of your LEGO parts. Now you have to put them all back into the original categories. How will you do this? You sort them by size and shape until they are each back into their specific place in the tray. What do you think you could have called the mess your younger sister created? That's right, it is a mixture. Fortunately, it was a physical change and she just made a simple mixture. You are able to separate them back into order. It's a good thing she did not toss them into the fireplace. That would have caused a chemical change as they all melted together. If your LEGOs were melted, you would be out of luck for building that next big project. 
    ::哦,不!你的妹妹刚刚把你们LEGO的所有部件都弄混了。 现在你必须把它们都放回原来的分类中。 你会怎么做呢? 你把它们按大小和形状排列,直到它们都回到托盘里的具体位置。 你认为你妹妹制造的烂摊子叫什么来着? 没错,这是混合体。幸运的是,这是物理变化,她只是做了一个简单的混合体。你可以把它们分开,你可以把它们重新分类。她没有把它们扔进壁炉,这是一件好事。当它们一起融化时,这会引起化学变化。如果你们的LEGO被熔化了,你就会为建造下一个大工程而走运。

    Mixtures
    ::混合物

    Mixtures keep their own identity when they combine. Therefore, they can usually be easily separated again. Their unique physical properties are used to separate them. For example, oil is less dense than water. Therefore, a mixture of oil and water can be separated by letting it stand. During this time the oil will float to the top.  Other ways of separating mixtures are shown in  Figure    and in the videos below.
    ::混合体在组合时保持自己的特性。 因此, 它们通常很容易再次分离。 它们独特的物理特性被用来分离它们。 例如, 油的密度比水低。 因此, 油和水的混合体可以通过让其站立来分离。 在此期间, 油会浮到顶端。 其它分离混合物的方法在图中和下面的视频中显示 。

    lesson content

     

    Separating the components of a mixture depends on their physical properties. Which physical property is used in each example shown here?
    ::混合物的成分分离取决于其物理特性,此处所举的每个例子都使用了哪一种物理属性?

    Lesson Summary
    ::经验教训摘要

    • Mixtures keep their own identity when they combine.
      ::混合体在结合时保持自己的特性。
    • Mixtures can usually be easily separated again.
      ::混合物通常很容易再分开。
    • A mixture's unique physical properties are used to separate them.
      ::混合体的独特物理特性用来分离它们。

    Lesson Review Questions
    ::经验回顾问题

    1. How could you use water and a coffee filter to separate a mixture of salt and sand?
      ::你们怎能用水和咖啡过滤器,把盐和沙子混合起来?
    1. What are some ways you could separate mixtures?
      ::你用什么方法来分离混合物?