长度的测量和基本数据处理讲义

1、专业好文档长度的测量和基本数据处理长度的测量和基本数据处理【实验目的实验目的】1、理解游标卡尺、螺旋测微计和移测显微镜的原理，掌握它们的使用方法；2、练习有效数字运算和误差处理的方法。【实验仪器和用品实验仪器和用品】游标卡尺（0125mm，0.02mm） 、螺旋测微计（025mm，0.01mm） 、移测显微镜（jcd3，0.01mm） 、空心圆管、小钢球等。【实验原理实验原理】1、游标卡尺的构造原理及读数方法游标卡尺分主尺和游标（副尺）两部分。主尺上刻有标准刻度 125mm。游标上均匀刻有 50 个分度，总长度为 49mm，游标上 50 个分度比标准的 50mm 短 1mm，1 个分度比标准的

2、 1mm 短mm，即 0.02mm，这 0.02mm 就是游标卡尺的最小分度值（即精度） 。游150标卡尺的卡口合并时，游标零线与主尺零线恰好对齐。卡口间放上被测物时，以游标零线为起点往前看，观察主尺上的读数是多少。假设读数是 xmm 多一点，这“多一点”肯定不足 1mm，要从游标上读。此时，从游标上找出与主尺上某刻度最对齐的一条刻度线，设是第 n 条，则这“多一点”的长度应等于 0.02nmm，被测物的总长度应为 l=(x+0.02n)mm。用这种规格的游标卡尺测量物体的长度时，以“mm”为单位，小数点后必有两位，且末位数必为偶数。游标上每 5 小格标明为 1 大格，每小格读数作 0.02m

3、m，每大格就应读作 0.10mm。从游标零线起往后，依次读作 0.02mm，0.04mm，0.06mm，直至第 5小格即第 1 大格读作 0.10mm。再往后，依次读作0.12mm，0.14mm，0.16mm，直至第 2 大格读作 0.20mm。后面的读数依此类推。游标卡尺不需往下估读。如图 1-5 应读作 61.36mm或 6.136cm2、螺旋测微器的构造原理及读数方法、螺旋测微器的构造原理及读数方法螺旋测微计主要由弓形体、固定套筒和活动套筒（微分套筒）三部分构成。螺旋测微计的测微原理是机械放大法。固定套筒上有一条水平拱线叫读数基线。基线上边是毫米刻度线，下边是半毫米刻度线。螺旋测微计的螺

4、距是 0.5mm，活动套筒每转动一周，螺杆就前进或者后退 0.5mm。活动套筒的边缘上均匀刻有 50 个分度，每转动一个分度，螺杆就前进或者后退mm 即 0.01mm。这 0.01mm 就是螺旋测微计的最小分度值（即精度） 。0.550实际测量时，分度线不一定正好与读数基线对齐，因此还必须往下估读到 0.001mm。可见，用螺旋测微计测量物体的长度时,以“mm”为单位，小数点后必有三位。读数时，先从固定套筒上读出大于半毫米的大数部分，再从活动套筒的边缘上读出小于半毫米的部分，二者0670345主尺游标图 1-5专业好文档图 1-7（a）主刻度尺读数 图 1-7（b）测微鼓轮读数之和就是被测物体

5、的总长度。这其中一定要注意观察半毫米刻度线是否露出来了。如图 1-6(a)应读作 5.272mm，图 1-6(b)应读作 5.772mm.使用螺旋测微计之前，必须先检查零点读数。先转动大棘轮使螺杆前进，当螺杆快要接触测砧时就应转动后面的小棘轮，听到“嗒嗒”声立即停止。如果此时活动套筒上的零线正好对齐读数基线，零点读数就记作 0.000mm，如果零线在读数基线以上，零点读数记作负，反之为正。每一次测量的直接读数减去零点读数才是真正的测量值，即测量值=直接读数零点读数。例如零点读数是-0.002mm，直接读数是 5.272mm，则测量值=5.272-（-0.002）=5.274（mm） 。3、读数

6、显微镜的构造原理及读数方法读数显微镜是将显微镜与螺旋测微计结合起来的长度精密测量仪器。其测微原理是光学放大法和机械放大法的综合。活动螺杆与显微镜筒通过螺旋相互啮合，转动活动螺杆右端的鼓轮，就可以使显微镜左右平移。测微螺旋的螺距为 1mm，鼓轮边缘上均匀刻有 100个分度，每转动一个分度镜筒就向左或向右平移 0.01mm。所以读数显微镜的最小分度值也是 0.01mm，读数时也要往下估读到 0.001mm。具体测量步骤是：（1）调节目镜，看到清晰的十字叉丝，并将叉丝调正；（2）将被测物平放到载物台上，并在镜筒的正下方，使被测长度的方向与镜筒平移的方向平行，然后调节镜筒升降旋钮，使镜筒缓慢的上升或下

7、降，进行调焦，直到看清物体的像，无视差；（3）转动鼓轮，平移镜筒，当叉丝的竖丝与物像的始端相切时，记下初读数 x1，读数方法如图 1-7（a）和 1-7（b）所示。继续沿同一方向平移镜筒，当竖丝与物像的末端相切时，记下末读数，则待测长度；2x21dxx05固定套筒图 1-6（a）3025微分套筒05固定套筒图 1-6 (b)3025微分套筒1x2x移动方向图 1-821dxx专业好文档（4）读数时，从固定刻度上读出大于 1mm 部分，从鼓轮边缘上读出小于1mm 的部分，二者之和就是 x1或 x2的值。测量时应注意的问题是，两次读数时镜筒必须是向同一个方向平移，不得移过了头又移回来，这样会产生空

8、程误差。如果不小心移过了头，必须多往回退一些距离，再重新沿原方向平移，对准被测点。如果简单地概括读数显微镜的原理和使用方法，就是“综合放大，同向平移，求差”【实验内容与要求实验内容与要求】1、用读数显微镜测量给定刻线的宽度，重复测量 6 次。2、用螺旋测微计测量小钢球的直径，沿不同径向测 6 次（注意：使用前应记录螺旋侧微计的零点读数）3、用游标卡尺测量空心圆管的外径、内径和高，重复测量 6 次。4、计算给定刻线的宽度和不确定度。5、计算钢球的体积和不确定度。6、计算空心圆管的体积。【实验注意事项实验注意事项】1、注意保护游标卡尺的卡口不被磨损，轻轻卡住即可读数，不能将被测物在卡口内移动，不能

9、跌。2、使用螺旋测微计时，当螺杆与被测物相距较近时就要转动尾部的小棘轮，听到“嗒嗒”声应立即停止。实验结束时，螺杆和测砧之间应留有小缝隙，不能拧死，以防热膨胀压坏精密螺丝。3、使用移测显微镜时，同一组读数应为沿同一方向平移读得的结果，否则会产生空程误差。镜头不能用手触摸。调焦时上、下移动筒一定缓慢，千万不能压坏物镜或被测物。【数据记录与处理数据记录与处理】表一 给定刻线宽度的测量 读数显微镜的仪器误差mm005. 0次序项目1234561()x mm2()x mm12|-|()dxxmm= 1234561()6dddddddmm= 2()()6 (6 1)iaddus dmm专业好文档= 3b

10、umm= 22()abu duumm= mm()ddu d表二 钢球直径的测量 仪器误差=0.004 零点读数 mm0d mm次序123456平均值不确定度)(dua直读值（）mm测量值（）mm= = 223)()( duduamm= = 316vd316vd3cm= = 212dvvddddd21( )()2u vd u d3cm= = ( )vvu v3cm 表三 圆管体积的测量 游标卡尺的仪器误差=0.02。mm次序项目123456平均值外径()d mm内径 ()d mm高()h mm= 22()4vddh22()4vddh3cm【思考题思考题】1、10 分度和 20 分度的游标卡尺，最

11、小分度值分别是多大？读数的末位有什么样的特点？2、比较一下游标卡尺和螺旋测微计，二者的读数方法有什么不同？专业好文档winger tuivasa-sheck, who scored two tries in the kiwis 20-18 semi-final win over england, has been passed fit after a lower-leg injury, while slater has been named at full-back but is still recovering from a knee injury aggravated against us

12、a.both sides boast 100% records heading into the encounter but australia have not conceded a try since josh charnleys effort in their first pool match against england on the opening day.aussie winger jarryd hayne is the competitions top try scorer with nine, closely followed by tuivasa-sheck with ei

13、ght.but it is recently named rugby league international federation player of the year sonny bill williams who has attracted the most interest in the tournament so far.the kiwi - with a tournament high 17 offloads - has the chance of becoming the first player to win the world cup in both rugby league

14、 and rugby union after triumphing with the all blacks in 2011.id give every award back in a heartbeat just to get across the line this weekend, said williams.the (lack of) air up there watch mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associatio

15、ns 150th anniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i have asked to meet yaya toure, he told bbc sport.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa

16、 has opened disciplinary proceedings against cska for the racist behaviour of their fans during citys 2-1 win.michel platini, president of european footballs governing body, has also ordered an immediate investigation into the referees actions.cska said they were surprised and disappointed by toures

17、 complaint. in a statement the russian side added: we found no racist insults from fans of cska. baumgartner the disappointing news: mission aborted.the supersonic descent could happen as early as sunda.the weather plays an important role in this mission. starting at the ground, conditions have to b

18、e very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. the balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/

19、8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. as he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.the balloon will slowly drift to the edge of space at 120,000 fee

20、t ( then, i would assume, he will slowly step out onto something resembling an olympic diving platform.they blew it in 2008 when they got caught cold in the final and they will not make the same mistake against the kiwis in manchester.five years ago they cruised through to the final and so far histo

21、ry has repeated itself here - the last try they conceded was scored by englands josh charnley in the opening game of the tournament.that could be classed as a weakness, a team under-cooked - but i have been impressed by the kangaroos focus in their games since then.专业好文档they have been concentrating on the sort of stuff that wins you tough, even contests - strong defence, especially on their own goal-line, completing sets and a go