问题 实验题

小明与小芳同学为了研究泡沫塑料和棉絮的保温性能好坏,两人设计并做了一个实验,他们用这两种材料分别包着装有热水的密闭烧瓶,让它们自然冷却,利用温度计和计时器定时测量两烧瓶中的水温随时间变化的情况。

  (1)为保证实验的准确性,实验前除了取大小、厚度相同的泡沫塑料和棉絮外,还应考虑影响水温变化的其他因素,即保持烧瓶相同、水的初温相同、环境因素相同和___________相同。

  (2)按照计划操作,小明与小芳同学把实验测得的时间和温度数据填在下列表格中: |

时间t/min010203040150180
泡沫塑料组水温T1/℃80645550412120
棉絮组水温T2/℃80564332282020
   分析上表数据可知:他们实验时的室内温度是__________℃。经过40min后,泡沫塑料包的烧瓶水温降低了_________℃;而棉絮包的烧瓶水温降低了_________℃。由此可以得出的实验结论是:_____________________________________。

  (3)除了采用相同时间内观察水降低的温度来比较这两种材料的保温性能外,根据上表数据你还可以采用________________________方法来比较这两种材料的保温性能。

答案

(1)热水质量   (2)20    39    52   泡沫塑料的保温性能比棉絮要好   (3)降低相同温度时,比较所用的时间长短

题目分析:研究泡沫塑料和棉絮的保温性能好坏,运用控制变量法研究。为保证实验的准确性,实验前除了取大小、厚度相同的泡沫塑料和棉絮外,还应考虑影响水温变化的其他因素,即保持烧瓶相同、水的初温相同、环境因素相同和热水质量相同。分析上表数据可知:他们实验时的室内温度是20℃。经过40min后,泡沫塑料包的烧瓶水温降低了39℃;而棉絮包的烧瓶水温降低了52℃。由此可以得出的实验结论是:泡沫塑料的保温性能比棉絮要好。除了采用相同时间内观察水降低的温度来比较这两种材料的保温性能外,根据上表数据你还可以采用降低相同温度时,比较所用的时间长短方法来比较这两种材料的保温性能。

考点:本试题考查的是对材料保温性能的研究。

点评:对于此类试题,学生应把握运用控制变量法研究。

阅读理解

阅读理解

     The US is one of the biggest countries in the world. It is well-known because its population comes

from all over the world. The immigrants(移民) can learn English to keep the United States united, but it

is unfair to have to drop their culture for an American way of life.

     I believe that recent immigrants should learn English in order to live in this country. If they don’t learn

English, they won’t be- able to communicate and do what they want. Anita, one of my mother’s friends,

came here from Ecuador(厄瓜多尔) three years ago. She does not speak English. One day her

daughter got a serious fever. She didn’t know what was going on, so she tried to call an ambulance(救

护车). However, when she called the hospital, she couldn’t talk. The operator(接线员) couldn’t

understand what Anita was saying. Thankfully, her sister arrived and called the ambulance. The doctor

told Anita that if she hadn’t arrived at the hospital in time, her daughter would have died.

    Immigrants should learn English to speak with the public, but they should also keep their language at

home. If we learn English only and forget our own language, we won’t be able to communicate with our

parents. Florence, my co-worker, speaks English only. Her mother didn’t teach her Spanish, her mother

language. She has lost her mother language, tradition and culture, so she can’t pass them down to her

future generations.

    In conclusion, immigrants should learn English in order to communicate with the public and to keep the

country united, but they shouldn’t drop their culture for an American way of life.

1. When Anita’s daughter was ill, Anita___________.

A. couldn’t speak

B. tried to call an ambulance

C. called her sister for help at once

D. sent her to the hospital immediately

2. The author mentions Anita’s experience mainly to show us __________.

A. English is a difficult language for immigrants to learn

B. immigrants should help each other in a strange country

C. it is necessary for immigrants to learn the common language

D. immigrants should keep their own language and culture

3. Florence is a woman who _______________.

A. can speak both English and Spanish

B. was born in Spain but grew up in the US

C. has given up her native culture

D. is one of the author’s classmates

4. Which of the following best describes the organization of the passage?

           A                               B                               C                             D

5. What’s the author’s attitude towards immigrants?

A. immigrants should learn English well

B. immigrants should speak their own language

C. immigrants have to drop their own culture for American way of life

D. immigrants should learn English as well as keep their own language

单项选择题