问题 问答题

在测量食用油密度的实验中

(1)步骤:(a)将天平放在水平台上;

(b)把游码移到标尺左端的______刻度处,调节平衡螺母,使横梁平衡;

(c)用天平测出装有适量食用油的烧杯的总质量m1

(d)将烧杯中的一部分食用油倒入量筒中,记录量筒中食用油的体积V;

(e)测出烧杯及剩下食用油的总质量m2,则量筒中食用油的质量为______;

(f)食用油的密度ρ=______.

(2)记录:请你根据以上步骤,设计一个记录表格.

(3)应用:“密度是物质的一种特性,它是不变的”.请你简要写出该物理知识的一种应用:______.

答案

(1)根据天平的使用规则:使用天平时要把天平水平放置在水平桌面上,将游码移至零刻度处.

      故答案为:零.

  量筒中食用油的质量等于原来烧杯内食用油及烧杯的总质量m1减去烧杯及剩下食用油的总质量m2

      故答案为:m1-m2

      因为量筒中食用油的质量为m1-m2.体积为v,所以根据密度公式ρ=

m
v
,得:

  食用油的密度ρ=

m1-m2
v

      故答案为:

m1-m2
v

    (2)根据实验步骤,设计表格如下:

烧杯和油的总质量m1/g烧杯和剩余油的质量m2/g量筒中油的质量(m1-m2)/g量筒中油的体积

v/cm3

食用油的密度

ρ/(g/cm3

     
    (3)密度在社会生活中有重要的价值,密度是物质的基本特性之一.每种物质都有自己的密度,并且是不变的.所以根据密度可以鉴别物质,测量物体质量,测量物体体积等.

     故答案为:鉴别物质,测量物体质量,测量物体体积等.

阅读理解

阅读理解

    Education is not an end, but a means to an end. In other words, we do not educate children only

for the purpose of educating them. Our purpose is to fit them for life.

     In some modern countries it has for some time been fashionable to think that by free education for

all - one can solve all the problems of society and build a perfect nation. But we can already see that

free education for all is not enough; we find in such countries a far larger number of people with

university degree; they refuse to do what they think "low" work; and, in fact, work with hands is thought

to be dirty and shameful in such countries. But we have only to think a moment to understand that the

work of a completely uneducated farmer is far more important than that of a professor; we can live

without education, but we die if we have no food. If no one cleaned our streets and took the rubbish

away from our houses, we should get terrible diseases in our towns…

     In fact, when we say that all of us must be educated to fit us for life, it means that we must be

educated in such a way that, firstly, each of us can do whatever work suited to his brains and ability

and, secondly, that we can realize that all jobs are necessary to society, and that is very bad to be

ashamed of one's work. Only such a type of education can be considered valuable to society.

1. The writer of the passage thinks that _______.

A. education can settle most of the world's problems

B. free education for all probably leads to a perfect world

C. free education won't help to solve problems

D. all the social problems can't be solved by education

2. The writer wants to prove that _______.

A. our society needs all kinds of jobs

B. our society needs free education for all

C. a farmer is more important than a professor

D. work with hands is the most important

3. The purpose of education is _______.

A. to choose officials for the country

B. to prepare children mainly for their future work

C. to let everyone receive education fit for him

D. to build a perfect world

4. The passage tells us about _______ of the education.

A. the means

B. the system

C. the value

D. the type

多项选择题