3.4 长度和数量
Section outline
-
How were sailors able to measure the depths of seas?
::水手如何测量海洋的深度?Back in the days before all the electronic gadgets for measuring depth and locating undersea objects existed, the "fathom" was the unit of measurement for depth. A rope was knotted every six feet and the end was dropped over the side of the ship. You could tell how deep the water was by how many knots went under the water before the rope hit bottom. Today we just turn on an instrument and read the depth to a high level of accuracy .
::早在所有测量深度和定位海底物体的电子工具存在之前的几天, “ fathom”是测量深度的单位。 绳子每六英尺结结一次, 终点掉在船的侧面。 您可以知道在绳子下沉之前水下有多少结, 水深多少。 今天, 我们只要打开一个仪器, 将深度读到高度精确度 。Length and Volume
::长度和数量Length is the measurement of the extent of something along its greatest dimension. The SI basic unit of length, or linear measure, is the meter (m). All measurements of length may be made in meters, though the prefixes listed in various tables will often be more convenient. The width of a room may be expressed as about 5 meters (m), whereas a large distance, such as the distance between New York City and Chicago, is better expressed as 1150 kilometers (km). Very small distances can be expressed in units such as the millimeter or the micrometer. The width of a typical human hair is about 20 micrometers (μm).
::长度是测量某个最大维度的长度。SI的基本长度单位,或线性测量单位,是米。所有长度的测量都用米表示,尽管不同表格中的前缀往往比较方便。一个房间的宽度可以表示为大约5米(m),而一长距离,如纽约市和芝加哥之间的距离,则以1 150公里(km)表示得更好。非常小的距离可以用毫米或微米等单位表示。典型的人类毛发宽度约为20微米(mm)。Volume is the amount of space occupied by a sample of matter. The volume of a regular object can be calculated by multiplying its length by its width by its height. Since each of those is a linear measurement, we say that units of volume are derived from units of length. The SI unit of volume is the cubic meter (m 3 ), which is the volume occupied by a cube that measures 1 m on each side. This very large volume is not very convenient for typical use in a chemistry laboratory. A liter (L) is the volume of a cube that measures 10 cm (1 dm) on each side. A liter is thus equal to both 1000 cm 3 (10 cm × 10 cm × 10 cm) and to 1 dm 3 . A smaller unit of volume that is commonly used is the milliliter (mL – note the capital L which is a standard practice). A milliliter is the volume of a cube that measures 1 cm on each side. Therefore, a milliliter is equal to a cubic centimeter (cm 3 ). There are 1000 mL in 1 L, which is the same as saying that there are 1000 cm 3 in 1 dm 3 .
::音量是物质样品所占的空间量。 普通物体的体积可以通过以其高度乘以其宽度乘以其宽度来计算。 由于每个物体都是线性测量, 我们说音量单位从长度单位中产生。 SI 体积单位是立方米( 立方米) 。 SI 体积单位是立方体( 立方体) , 每边测量1米。 这个非常大体量对于化学实验室的典型使用并不十分方便。 立方体( 立方体) 每侧测量10厘米(1 dm) 。 因此, 每立方体的体量等于1000厘米( 立方厘米) 。 1升的升等于1000 立方厘米, 通常使用的体积小于毫立方( 立方公尺) 。 毫立方体是每立方公尺1米3的立方体体体量。 因此, 毫立方体等于1立方厘米, 1升为1000 立方公尺, 这与1米3的体相同。A typical water bottle is 1 liter in volume
::典型的水瓶容量为1升1升Rubik’s cube. This Rubik’s cube is 5.7 cm on each side and has a volume of 185.2 cm 3 or 185.2 mL.
::Rubik 的立方体。 魔方的立方体每侧5.7厘米,体积为185.2厘米3或185.2毫升。Graduated cylinder. Volume in the laboratory is often measured with a graduated cylinder, which come in a variety of sizes.
::实验室的体积通常用一个不同尺寸的已毕业气瓶测量。Summary
::摘要-
Length is the measurement of the extent of something along its greatest dimension.
::长度是衡量某种事物在最大维度上的程度。 -
Volume is the amount of space occupied by a sample of matter.
::体积是样品物质占用的空间量。 -
Volume can be determined by knowing the length of each side of the item.
::量的确定取决于项目每一侧的长度。
Review
::回顾-
Define length.
::界定长度。 -
Define volume.
::确定数量。 -
An object measures
. Which value is the length of the object?
::物体的度量 6.2 cm×13.7 cm×26.9 cm。 物体的长度是多少? -
How big is a mL?
::一个ML有多大?
-
Length is the measurement of the extent of something along its greatest dimension.
