章节大纲

  • Lesson Objectives
    ::经验教训目标

    • Compare and contrast the basic properties of matter, such as mass and volume.
      ::比较和对比物质的基本特性,例如质量和体积。

    Lesson Vocabulary
    ::词汇表课程

    • solid
      ::固体
    • liquid
      ::液态液体
    • gas
      ::气体气体气体
    • mass
      ::质量
    • volume
      ::音量量
    • physical property
      ::物质财产或物质财产或物质财产的
    • matter
      ::事项
    • state of matter
      ::事态状况
    • atom
      ::原子原子

    What’s the Matter?
    ::有何贵干?

    Here is a riddle for you to ponder: What do you and a tiny speck of dust in outer space have in common? Think you know the answer?  
    ::这是你们所能思考的一个谜题:你们和外层空间的微小的尘埃有何共同之处?你们知道答案吗?

    Both you and the speck of dust consist of matter. So does the ground beneath your feet. In fact, everything you can see and touch is made of matter. The only things that are not matter are forms of energy. This would include things such as light and sound. Although forms of energy are not matter, the air and other substances they travel through are. So what is matter? Matter is defined as anything that has mass and volume. You may recall that atoms are the building blocks of matter.
    ::你们和尘埃的微尘都是由物质构成的,脚下的地面也是由物质构成的。事实上,你们所能看见的和触摸的,都是由物质构成的。非物质只是能量的形式。这包括光和声音等物质。虽然能源的形式无关紧要,但空气和其他物质是它们穿行的。什么是物质?物质的定义是任何有质量和体积的东西。你们或许记得原子是物质的构件。

    Even things as small as atoms have mass and volume. The more atoms, or matter, the more mass and volume are present. Different types of atoms have different amounts of mass and volume. So, it's not enough to know the count of atoms to determine the mass. You must also know the type of atoms an item is made of.  Mass and volume are just two ways to describe the physical property of a substance.  Physical properties are all determined by the amounts and type of atoms that compose items. 
    ::即使原子那么小的东西也有质量和体积。 原子或物质越多, 质量和体积就越大。 不同种类的原子质量和体积不同。 因此, 光知道原子的数数不足以确定质量。 您也必须知道一个物体的原子类型。 质量和体积只是描述物质物理属性的两种方式。 物理特性都取决于组成物体的原子的数量和类型。

    Mass
    ::质量质量质量质量

    Mass  refers to the amount of matter. Mass is usually measured with a balance. A balance allows an object to be matched with other objects of known mass. The SI unit for mass is the kilogram. For smaller masses, grams are often used instead. 
    ::质量指物质的数量。质量通常以平衡度衡量。平衡度允许将物体与其他已知质量对象匹配。质量的SI单位为千克。对于较小的质量,则通常使用克。

    You may have a balance in your classroom. The balance may be either a triple-beam balance or an electronic balance. The figure below of the old-fashioned balance may give you a better idea of what mass is. What does it mean when both sides of the balance are at the same level? That's correct, it would mean the masses of each object are equal. In that case, the fruit would have a mass of 1 kg. It would have the same mass as the iron. As you can see, the fruit is at a higher level than the iron. This means the fruit has less mass than the 1 kg iron object.
    ::你可以在教室里保持平衡。 平衡可以是三束平衡, 也可以是电子平衡。 旧式平衡的下方图可以让你更好地了解质量。 当平衡的两侧处于同一水平时, 这意味着什么 ? 正确, 这意味着每个对象的质量是相等的。 如果是这样, 水果的重量为1公斤。 它的重量与铁一样。 正如你可以看到的那样, 水果的含量比铁的要高。 这意味着水果的重量比1公斤铁的重量要小。

    Q:  What If the fruit were at a lower level than the iron object?
    ::问题:如果果实的含量低于铁质物体,怎么办?

    A:  The mass of the fruit would be greater than 1 kg.
    ::甲:水果质量将大于1公斤。

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    Mass versus Weight
    ::质量对体重

    Mass is often confused with weight. The two are closely related, but they are not the same. Mass is the amount of matter. Weight is a measure of the force of gravity acting on the mass. On Earth, the force of gravity is constant. If we are comparing objects on Earth, objects with a greater mass also have a greater weight. 
    ::质量通常与重量混为一谈。 两者是密切相关的, 但并非相同。 质量是物质的数量。 重量是测量质量上发生作用的重力的尺度。 在地球上, 重力是恒定的。 如果我们比较地球上的物体, 质量较大的物体的重量也更大。

    Weight is measured with a device called a scale. Remember, mass is measured with a balance. You might find an example of a scale in your kitchen or bathroom. Scales detect how forcefully objects are being pulled downward by gravity. The SI unit for weight is the newton (N). A mass of 10 kg has a weight of 100 newtons (N). 
    ::体重是用一个叫做比例尺的设备测量的。 记住, 质量是用平衡来衡量的。 您可以在厨房或浴室中找到一个比例尺的例子。 比例尺可以检测到重力如何将物体拉下。 重力的 SI 单位是牛顿( N ) 。 10千克的重量为100 牛顿( N ) 。

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    Problem Solving
    ::解决问题

    At Earth's gravity, what is the weight in newtons of an object with a mass of 10 kg?
    ::在地球的重力下,质量为10公斤的物体的牛顿重量是多少?

    At Earth's gravity, 1 kg has a weight of 10 N. Therefore, 10 kg has a weight of (10 kg x 10 m/s 2 ) = 100 N.
    ::在地球重力下,1公斤的重量为10牛顿。 因此,10公斤的重量为10公斤x10米/秒=100牛顿。

    You Try It!
    ::你试试看!

    If you have a mass of 50 kg on Earth, what is your weight in newtons?
    ::如果你在地球上的重量为50公斤,那么你的牛顿重量是多少?

    An object with more mass is pulled by gravity with greater force. Mass and weight are closely related. However, the weight of an object can change if the force of gravity changes. On Earth, the force of gravity is the same everywhere. So how does the force of gravity change? It doesn't if you stay on Earth. What if we travel to another planet or moon in our solar system?
    ::重力拉动一个质量较大的物体。 质量和重量是密切相关的。 但是, 当重力改变时, 物体的重量会改变。 在地球上, 重力是相同的。 那么引力是如何变化的? 如果你留在地球上, 它不会改变。 如果我们去太阳系中的另一个行星或月球呢?

    Look at the photo of astronaut Edwin E. Aldrin Jr. taken by fellow astronaut Neil Armstrong in the  Figure   . They were the first humans to walk on the moon. An astronaut weighs less on the moon than he would on Earth. This is because the moon's gravity is weaker than Earth's. The astronaut's mass, on the other hand, did not change. He still contained the same amount of matter on the moon as he did on Earth.
    ::看看宇航员Edwin E. Aldrin Jr. 在图中被宇航员Neil Armstrong拍摄的照片。 他们是最早在月球上行走的人。 宇航员在月球上的重量比在地球的体重要低。 这是因为月球的重力比地球的轻。 另一方面,宇航员的质量并没有改变。 他仍然在月球上拥有与在地球相同的物质。

    If the astronaut weighed 175 pounds on Earth, he would have weighed only 29 pounds on the moon. If his mass on Earth was 80 kg, what would his mass have been on the moon? [Figure 3]
    ::如果宇航员在地球上的重量为175磅,那么在月球上,他只有29磅。 如果他在地球上的质量为80公斤,那么他在月球上的质量是多少? [图3]

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    Volume
    ::量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量量

    The amount of space matter takes up is its volume. How the volume of matter is measured depends on its state.
    ::空间物质吸收的数量是其体积,如何测量物质体积取决于其状态。

    The volume of liquids is measured with measuring containers. In the kitchen, liquid volume is usually measured with measuring cups or spoons. In the lab, liquid volume is measured with containers such as graduated cylinders. Units in the metric system for liquid volume include liters (L) and milliliters (mL).
    ::液体量用测量容器测量,在厨房里,液体量通常用测量杯子或勺子测量,在实验室里,液体量用诸如分级气瓶等容器测量。

    The volume of gases depends on the volume of their container. That's because gases expand to fill whatever space is available to them. For example, as you drink water from a bottle, air rushes in to take the place of the water. An "empty" liter bottle actually holds a liter of air. How could you find the volume of air in an "empty" room?
    ::气体的量取决于其容器的容量。 这是因为气体会膨胀, 以填满它们所拥有的空间。 例如, 当你喝瓶水时, 空气会冲进来代替水。 “ 空的” 公升瓶子实际上含有一升空气。 您如何能在“ 空的” 房间里找到空气量 ?

    The volume of regularly shaped solids can be calculated from their dimensions. For example, the volume of a rectangular solid is the product of its length, width, and height ( l  x  w  x  h ). For solids that have irregular shapes, the displacement method is used. You can see how it works in the video below. The SI unit for solid volumes is cubic meters (m 3 ). However, cubic centimeters (cm 3 ) are often used for smaller volume measurements. 
    ::固定形固体的体积可以从其尺寸计算出来。例如,矩形固体的体积是其长度、宽度和高度(l x w x h)的产物。对于形状不固定的固体,则使用脱位法。您可以看到下面的视频是如何工作的。固态体体积的SI单元是立方米(立方米)。然而,立方厘米(立方厘米)往往用于较小的体积测量。

    The displacement method is used to find the volume of irregularly shaped objects. It measures the amount of water that the object displaces, or moves out of the way. What is the volume of the toy dinosaur in mL? [See  Figure  ]
    ::离位法用于查找非正常形状物体的数量,测量物体转移或移动的水量。微升中的玩具恐龙的数量是多少? [见图

     

     

    Q:  How could you find the volume of air in an otherwise empty room?
    ::问题:你怎么能在空房里找到空气量?

    A:  If the room has a regular shape, you could calculate its volume from its dimensions. For example, the volume of a rectangular room can be calculated with this formula:
    ::A: 如果房间有一个常规形状, 您可以从它的尺寸来计算它的体积。 例如, 矩形房间的体积可以用这个公式来计算 :

    Volume = length × width × height

    If the length of the room is 5.0 meters, the width is 3.0 meters, and the height is 2.5 meters, then the volume of the room is:
    ::如果房间的长度是5.0米,宽度是3.0米,高度是2.5米,那么房间的体积是:

    Volume = 5.0 m × 3.0 m × 2.5 m = 37.5 m 3

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    Q:  What is the volume of the dinosaur in the diagram above?
    ::问题:上面图中恐龙的体积是多少?

    A:  The volume of the water alone is 4.8 mL. The volume of the water and dinosaur together is 5.6 mL. Therefore, the volume of the dinosaur alone is 5.6 mL – 4.8 mL = 0.8 mL.
    ::A:单是水量为4.8毫升,水量和恐龙体积为5.6毫升。 因此,单是恐龙体积为5.6毫升 - 4.8毫升=0.8毫升。

    Advanced Topic: Defining Density
    ::高级专题:界定密度

    Density  is also an important physical property of matter. The concept of density combines what we know about an object's mass and volume. Density reflects how closely packed the particles of matter are. When particles are packed together more tightly, matter is more dense. Differences in density of matter explain many phenomena. It explains why helium balloons rise. It explains why currents such as the Gulf Stream flow through the oceans. It explains why some things float in or sink. You can see this in action by pouring vegetable oil into water. You can see a colorful demonstration in this video.
    ::密度也是一个重要的物质物理属性。 密度概念将我们所了解的物体质量和体积结合起来。 密度反映物质粒子的紧凑程度。 当粒子被集中在一起时, 物质密度会更稠密。 物质密度的差异可以解释许多现象。 它解释了为什么气球上升。 它解释了为什么流水流在海洋中流动。 它解释了为什么有些东西会漂浮在或沉入水中。 您可以将植物油倒入水中来观察这一点。 您可以在视频中看到一个多彩的演示 。

     

     

    To better understand density, think about a bowling ball and volleyball, pictured in the  Figure  . Imagine lifting each ball. The two balls have about the same volume. The bowling ball feels much heavier than the volleyball, but why? It is because the bowling ball is made of solid plastic. Plastic contains a lot of tightly packed particles of matter. In contrast, the volleyball is full of a gas (air). The air atoms are further apart than in the solid bowling ball. Therefore, the matter inside the bowling ball is more dense than the matter inside the volleyball. 
    ::为了更好地了解密度,请想一想一个保龄球和排球,如图所示。想象一下每个球的举起量。两个球的体积大致相同。保龄球比排球重得多,但为什么?这是因为保龄球是由固态塑料制成的。塑料含有大量紧凑的物质粒子。相反,排球装满了气体(空气)。空气原子比固态保龄球的体积要大得多。因此,保龄球内的物质比排球内的物质密度要大。

    A bowling ball is denser than a volleyball
     
    A bowling ball is denser than a volleyball. Although both balls are similar in size, the bowling ball feels much heavier than the volleyball.

    Q:  If you ever went bowling, you may have noticed that all the bowling balls are the same size. This means they have the same volume. Even though they are the same size, some bowling balls feel heavier than others. How can this be?
    ::问题:如果你去打保龄球,你可能注意到所有的保龄球大小都一样。这意味着它们体积相同。即使它们体积相同,但有些保龄球比其他保龄球更重。这怎么可能呢?

    A:  Bowling balls that feel lighter are made of matter that is less dense.
    ::A:感觉较轻的保龄球是由不太密集的物质造成的。

    Calculating Density
    ::计算密度

    The density of matter is actually the amount of matter in a given space. The amount of matter is measured by its mass. The space matter takes up is measured by its volume. Therefore, the density of matter can be calculated with this formula:
    ::物质密度实际上是在给定空间中的物质数量。 物质数量根据其质量测量。 空间物质接收量根据其体积测量。 因此, 物质密度可以用这个公式来计算 :

    Density=massvolume

    Assume, for example, that a book has a mass of 500 g and a volume of 1000 cm 3 . Then the density of the book is:
    ::例如,假设一本书的质量为500克,体积为1000厘米3。 那么书的密度是:

    Density=500 g1000 cm3=0.5 g/cm3

    Q:  What is the density of a liquid that has a volume of 30 mL and a mass of 300 g?
    ::问题:体积为30毫升、质量为300克的液体的密度是多少?

    A:  The density of the liquid is:
    ::A:液体密度为:

    Density=300 g30 mL=10 g/mL

    Lesson Summary
    ::经验教训摘要

    • Matter is all the “stuff” that exists in the universe. It has both mass and volume.
      ::物质是宇宙中存在的“物质 ” 。 它有质量和体积。
    • Mass measures the amount of matter in a substance or an object. The basic SI unit for mass is the kilogram (kg).
      ::物质或物体中物质或物体的量量物质质量。 基本SI质量单位为千克。
    • Volume measures the amount of space that a substance or an object takes up. The basic SI unit for volume is the cubic meter.
      ::量度物质或物体所占用的空间大小。 量的基本 SI 单位是 立方米 。
    • Density is an important physical property of matter. It reflects how closely packed the particles of matter are.
      ::密度是物质的重要物理属性,反映了物质粒子的紧凑程度。

    Lesson Review Questions
    ::经验回顾问题

    1. How do scientists define matter?
      ::科学家如何界定物质?
    1. What is mass? What is the basic SI unit of mass?
      ::什么是质量?基本SI质量单位是什么?
    1. What does volume measure? Name two different units that might be used to measure volume.
      ::什么是量度? 列出两个不同的单位, 可用于量度体积 。
    1. Explain how to use the displacement method to find the volume of an irregularly shaped object.
      ::解释如何使用移位方法来寻找不规范形状物体的体积。
    1. What is density?
      ::什么是密度?
    1. Find the density of an object that has a mass of 5 kg and a volume of 50 cm 3 .
      ::查找质量为5公斤、体积为50厘米3的物体的密度。
    1. Create a sketch that shows the particles of matter in two substances that differ in density. Label the sketch to show which substance has greater density.
      ::创建一张草图, 显示两种不同密度的物质中物质的粒子 。 标签显示哪些物质密度更高 。
    1. How does mass differ from weight?
      ::质量与重量有何不同?
    1. Describe the displacement method for measuring the volume of an object.
      ::描述测量物体体积的移位方法。

    Apply Concepts
    ::应用概念

    1. Create a table comparing and contrasting physical properties of tap water and table salt.
      ::建立一个表格,比较和对比自来水和桌盐的物理特性。
    1. Apply the concept of density to explain why oil floats on water.
      ::运用密度概念来解释为什么浮在水上石油。

    Think Critically
    ::仔细仔细思考

    1. Some kinds of matter are attracted to a magnet. Is this a physical or chemical property of matter? How do you know?
      ::磁铁吸引了某种物质。 这是物质的物理或化学属性吗? 你怎么知道?

    Points to Consider
    ::需要考虑的要点

    • The physical and chemical properties of substances can be used to identify them. That’s because different kinds of matter have different properties.
      ::物质的物理和化学特性可以用来识别它们。 这是因为不同的物质具有不同的特性。
    • What property could you use to tell the difference between iron and aluminum?
      ::你用什么财产来分辨铁和铝的区别?
    • How could you tell whether a liquid is honey or vinegar?
      ::你怎么知道液体是蜂蜜还是醋?