问题 问答题

在我省举行的初中化学实验创新竞赛中,我市教师设计了下面一个实验并获得大奖,让我们一起来分享:

实验装置:

实验操作:

1.用一个小集气瓶集满一瓶氧气,将带火星的木条放在集气瓶口,观察到,说明氧气具有______的性质;

2.将另一个“空”集气瓶倒扣在装氧气的集气瓶上,瓶口相接,等待4-5分钟;

③然后将上面的“空”集气瓶用玻璃片盖好取下来,再将带火星的小木条分别伸入两个集气瓶内,观察到和步骤①同样的现象.

实验结论及应用:该实验说明分子______;请你再列举一个能用该结论解释的生活中的现象______;

评价:该实验比课本氨分子运动的实验突出的优点是______.

反思:纯氧能使带火星的木条复燃,反之能使带火星的木条复燃的气体______(填“一定”或“不一定”)是纯氧.

再探究:针对上述物质燃烧剧烈问题,我设计的方案是:

操作步骤______.

现象______.

答案

1.氧气能使带火星的木条复燃,说明氧气有助燃性或氧化性;

2.两瓶气体能混合说明了分子的不断运动,可以从闻到气味角度举例说明分子运动;该实验建立在原有知识的基础上,学生易接受,且趣味性比较强,还比较环保.氧气达到一定浓度就能使带火星木条复燃;

设计方案从同种物质在空气和在氧气中燃烧现象不同设计.

故答案为:1.支持燃烧2.分子能不断运动;打开汽油瓶盖能闻到汽油的气味等;充分利用学生已有的旧知识探究新知识;环保;操作简单;趣味性;保护学生的健康;不一定;

将等质量相同的木炭点燃后分别放入盛有空气和氧气的集气瓶中,在氧气中比在空气中燃烧剧烈.

阅读理解

“Sesame Street” has been called “the longest street in the world”. That is because the television program by that name can now be seen in so many parts of the world. That program became one of American’s exports soon after it went on the air in New York in 1969.

In the United States more than six million children watch the program regularly. The viewers include more than half the nation’s pre-school children, from every kind of economic(经济的), racial(种族的), and geographical group.

Although some educators object to certain elements in the program, parents praise it highly. Many teachers also consider it a great help, though some teachers find that problems arise when first graders who have learned from “Sesame Street” are in the same class with children who have not watched the program.

Tests have shown that children from all racial, geographical, and economic backgrounds have benefited from watching it. Those who watch it five times a week learn more than occasional(偶然的) viewers. In the US the program is shown at different hours during the week in order to increase the number of children who can watch it regularly.

The programs all use songs, stories, jokes, and pictures to give children a basic understanding of numbers, letters and human relationships. But there are some differences. For example, the Spanish program, produced in Mexico City, devotes more time to teaching whole words than to teaching separate letters.

Why has “Sesame Street” been so much more successful than other children’s shows? Many reasons have been suggested. People mention the educational theories(理论) of its creators, the support by the government and private(私人的) businesses, and the skillful use of a variety of TV tricks. Perhaps an equally important reason is that mothers watch it along with their children. This is partly because famous adult stars often appear on it. But the best reason for the success of the program may be that it makes every child watching feel able to learn. The child finds himself learning, and he wants to learn more.

小题1:“Sesame Street” is actually _______.

A.a street in the US

B.a program for children

C.a program for teachers

D.a program for students小题2:Children who often watch the program _______.

A.can have problems in school

B.will find it a great help

C.will take no interest in their studies

D.will be well educated小题3: What is special about the program?

A.It offers great fun.

B.It makes children feel able to learn.

C.It is shown at different hours during the week.

D.Children learn and enjoy themselves while watching.小题4: Why is “Sesame Street” so popular in the world?

A.Because it is supported by the government and businesses.

B.Because it uses a variety of skillful tricks.

C.Because mothers watch it along with their children.

D.Because it makes every child watching it feel able to learn.小题5:The best title for this passage can be _______.

A.TV Programs

B.Educating Children

C.Sesame Street

D.A Great Success

单项选择题