Section outline


  • lesson content

    David is measuring the  length  of a textbook so he can cover his book with paper for a project. He normally uses a customary ruler to measure, but he does not have one with him, and the only tool he has measures in metric units. David needs help figuring out which metric unit of measurement he should use to measure his text book so he can finish his project. 
    ::大卫正在测量教科书的长度,这样他就可以用论文来覆盖他的书。 他通常使用传统标尺来测量。 他通常使用传统标尺来测量,但他没有与他一起测量,而他唯一的工具是量度单位。 大卫需要帮助弄清楚他应该用哪个计量单位来衡量他的教科书,这样他才能完成项目。

    In this concept, you will learn how to determine the best use of each metric unit of length.
    ::在这个概念中,你们将学会如何确定每一公吨长度单位的最佳用途。

    Metric System
    ::计量系统

    In science classes, and anywhere outside of the United States, length is measured with the  Metric System .  The most common units that we use to measure length in the metric system are the  millimeter ,  centimeter ,  meter , and  kilometer . 
    ::在科学班级中,以及在美国以外的任何地方,长度都是用米克系统测量的。 我们用来测量公制中长度的最常用单位是毫米、厘米、米和公里。

    The  millimeter  is the smallest commonly used unit in the metric system. The abbreviation for millimeters is mm (for example, 3 mm). A millimeter would be used to measure something that is very small, like a seed.
    ::毫米是公制中最小的常用单位。 毫米的缩写是毫米( 例如, 3毫米 ) 。 一毫米将用来测量非常小的东西, 如种子 。

    The  centimeter  is the next smallest unit of measurement. The abbreviation for   is cm (for example, 3 cm). Centimeters are smaller than  inches . One centimeter is roughly the width of a staple. There are 10 millimeters in one centimeter.
    ::厘米是下一个最小的测量单位。缩略语是厘米(例如,3厘米)。厘米小于英寸。一厘米大致是主食的宽度。一厘米有10毫米。

    On most rulers, both the customary units of measurement and the metric units of measurement are shown, so you can see millimeters marks, centimeter marks and inch marks. 
    ::在大多数标尺上,既显示习惯的测量单位,又显示测量的计量单位,这样你可以看到毫米标记、厘米标记和英寸标记。

    The next common metric unit is the  meter . The abbreviation for the meter is m (for example, 8 m). A meter is longer than a  foot ; in fact, a meter is roughly about the same length as a  yard . One way to get an idea of the length of a meter is to stretch your arms out to your sides and your fingertip to fingertip shows about a meter. One meter is much longer than one centimeter. There are actually 100 centimeters in one meter.   are used to measure bigger objects or longer distances, such as the depth of a pool or length of a hallway.  
    ::下一个通用的公分单位是米。米的缩略语是米(例如,8米)。米长于一英尺;事实上,米大约与院子的长度大致相同。一个方法就是将手臂伸展到两侧,指尖指尖显示一米。一米长于一厘米。实际上,一米有100厘米。用来测量更大的物体或更长的距离,例如游泳池的深度或走廊的长度。

    Kilometers  are the longest unit of metric measurement. The abbreviation for kilometers is km (for example, 12 km). Like miles, kilometers are used to measure long distances, such as the distance from your house to the store or from one town to another. Kilometers are a little more than 1/2 a  mile , and they are much longer than meters. There are 1,000 meters in a kilometer.
    ::公里是衡量量最长的单位。 公里的缩略语是公里( 例如, 12公里 ) 。 和英里一样, 公里被用来测量长的距离, 比如从你家到商店或从一个镇到另一个镇的距离。 公里小于1.5英里, 长于1/2米。 公里有1,000米。 公里有1,000米。

    Examples
    ::实例

    Example 1
    ::例1

    Earlier, you were given a problem about David and his text book he was covering for a project.
    ::早些时候,你得到一个问题 关于大卫和他的教科书 他为一个项目所覆盖。

    He needs to measure the length of the book so he can get the right amount of paper to cover it. He needs to use metric units and his options are millimeters, centimeters, meters or kilometers. Which unit of measurement should David use to measure his textbook?
    ::他需要测量书的长度,以便获得适当的纸张来覆盖它。他需要使用量度单位,他的选择是毫米、厘米、米或公里。 大卫应该用哪个量度单位来衡量他的教科书?

    First, consider the object David is measuring. David needs to get his textbook out in front of him as a reference.
    ::首先,考虑大卫正在测量的物体。大卫需要把他的教科书拿出来作为参考。

    Next, David needs to think about the metric units and decide which ones make sense as possibilities. He now knows kilometers are used to measure long distances, so that is ruled out. He also knows a meter is much longer than a text book, so he can rule out meters as well. He needs to decide between using millimeters or centimeters. 
    ::接下来,大卫需要考虑测量单位,决定哪些单位是可行的。他现在知道公里用来测量长距离,所以排除了这一点。他还知道一个计时器比教科书长得多,因此他也可以排除米。他需要决定使用毫米或厘米。

    Then, David will match the appropriate choice with the object he is measuring. He knows millimeters measure very small objects like seeds or staples. His textbook is much larger than those types of objects, so centimeters are the right choice for measuring his book.
    ::然后,大卫会将合适的选择与其测量的物体匹配。他知道毫米测量了种子或主食等非常小的物体。他的教科书比这些种类的物体要大得多,因此厘米是测量其书本的正确选择。

    The answer is centimeters.
    ::答案是厘米。

    David will use centimeters to measure his textbook to complete his project.
    ::大卫将用厘米测量他的教科书 来完成他的计划

    Example 2
    ::例2

    Which unit of metric measurement would you use to measure the length of a piece of paper?
    ::你用哪一计量单位来衡量一张纸的长度?

    First, take out a sample of the object you are measuring, or picture it in your mind.
    ::首先,取出你正在测量的物体的样本, 或者在你的脑海里想象一下。

    Next, think about your metric units and consider which units make sense with this object. There are millimeters, centimeters, meters and kilometers as the most commonly used units of metric measurement. If possible, rule out units that are definitely not appropriate to measure the object. Kilometers are about a half of a mile and are used to measure long distances, so that unit is not appropriate. Meters are about the size of a yard, or your wingspan, so that is also not appropriate. That leaves us with millimeters and centimeters.
    ::接下来,请考虑一下您的度量单位, 并且考虑哪个单位与该天体有关系。 有毫米、 厘米、 米和公里作为最常用的度量单位。 如果可能的话, 排除绝对不适合测量天体的单位。 千米大约为半英里, 用来测量长距离, 这样不合适 。 测距与院子大小或机翼大小有关, 因此也不合适 。 这给我们留下了毫米和厘米。

    Then, match the appropriate unit with the object you are measuring. Millimeters are tiny units used to measure very small objects that are even sometimes hard to see. You can see a piece of paper quite well, so you would not use millimeters for this size of an object. Centimeters are the most appropriate unit to measure the length of a piece of paper.
    ::然后,将合适的单位与您正在测量的物体匹配。 毫米是用于测量非常小的物体的小单位, 有时甚至很难看到这些物体。 您可以非常清楚地看到一块纸, 这样您就不会使用毫米来测量一个物体的大小。 厘米是测量一块纸张长度的最合适的单位 。

    The answer is centimeters.
    ::答案是厘米。

    Example 3
    ::例3

    What unit of measurement would you use to measure the distance around a track?
    ::您用什么单位测量音轨的距离 ?

    First, consider the object you are measuring and look at it or picture it in your mind.
    ::首先,考虑一下你正在测量的物体,然后看看它,或者想象一下它。

    Next, consider your unit of measurement choices. A track is a large object to measure so you would definitely rule out millimeters and centimeters. That leaves meters and kilometers.
    ::接下来,请考虑您的测量选择单位。 轨迹是一个要测量的大物体, 这样你绝对可以排除 毫米和厘米。 那会留下米和公里。

    Then, match the object with the best appropriate unit of measurement. Long distances like a track or distance around a block etc. are often measured by kilometers. Meters are used to measure things that are closer together, like lengths of houses or pools. The appropriate unit in this example is kilometers.
    ::然后,将对象与最适合的测量单位匹配。 长距离, 如轨道或街区周围的距离等, 通常用公里来测量。 鼠标用来测量相近的东西, 如房屋或池塘的长度。 此示例中适当的单位是公里 。

    The answer is kilometers.
    ::答案是公里。

    Example 4
    ::例4

    What unit of measurement would you use to measure the length of an apple seed?
    ::您用什么单位来衡量苹果种子的长度 ?

    First, get the object out to measure or picture it in your mind.
    ::首先,把对象拿出来 测量或想象它 在你的脑海中。

    Next, think about the reasonable measurement choices. Kilometers are much to large to measure such a small object, as well as meters. That leaves centimeters and millimeters are the two possibilities.
    ::接下来,想想合理的测量选择。公里对于测量如此小的物体和米来说是大到很大的。留下厘米和毫米是两种可能性。

    Then, match the object with the best unit of measurement. Centimeters are 10 times bigger than millimeters, and could be difficult to get a close measurement with the larger unit; therefore, millimeters would give the most accurate measurement. 
    ::然后,将对象与最佳测量单位匹配。 厘米比毫米大10倍, 并且可能很难与更大的单位进行近距离测量; 因此, 毫米可以给出最准确的测量。

    The answer is millimeters.
    ::答案是毫米。

    Example 5
    ::例5

    What unit of measurement would you use to measure the length of a paper clip?
    ::您用什么单位来衡量纸张剪辑的长度?

    First, get out a paper clip or picture one in your mind.
    ::首先,拿出一张纸片 或者在你的脑海里画一张

    Next, consider the unit choices that make sense with the object. A paper clip is very small, so kilometers and meters do not make sense. That leaves two choices: millimeters and centimeters.
    ::接下来,请考虑一下与对象相关的单位选择。 剪贴片非常小, 所以公里和米是没有意义的。 这就留下了两个选择: 毫米和厘米。

    Then, match the object with the appropriate unit. A paper clip could be measured with either unit (millimeter or centimeter) but a millimeter is the more appropriate size to get an accurate measurement.
    ::然后,将对象与合适的单位匹配。纸片片段可以用一个单位(毫米或厘米)测量,但一毫米的大小更适合进行精确测量。

    The answer is millimeters.
    ::答案是毫米。

    Review
    ::回顾

    Choose the appropriate unit of length using metric units for each item listed below.
    ::使用以下每一项目的计量单位选择适当的长度单位。

    1. The depth to plant a seed in the soil
      ::在土壤中种种子的深度
    2. The height of a tree
      ::树的高度
    3. The area of a garden plot
      ::园地的面积,
    4. The distance from a garden to the local farm store
      ::从花园到当地农场商店的距离
    5. The length of a carrot
      ::胡萝卜的长度
    6. A stretch of fencing
      ::栅栏的伸展
    7. The length of a hoe
      ::hoe 的长度
    8. The distance between two seedlings planted in the ground
      ::埋在地面上的两个幼苗之间的距离
    9. The height of a corn stalk
      ::玉米尾巴的高度
    10. A road race
      ::道路竞赛
    11. A grub collected from the garden
      ::从花园里收集的一小块食物
    12. The width of a garden row
      ::园艺行宽度
    13. The length of a garden row
      ::园艺行的长度
    14. The size of a small seed
      ::小种子的大小
    15. The distance that a tractor can travel on a large farm per day
      ::一部拖拉机每天在大型农场上行驶的距离