问题 问答题

小李在研究“影响浮力大小的因素”时,根据自己的经验感受提出:“在同种液体中,固体所受的浮力大小与排开液体的体积成正比.”现有实验器材:天平、砝码、多个完全相同的钩码、足够大的量筒、足量的水、细线.请你根据提供的器材设计一个实验验证小李的猜想.简明陈述实验步骤.

实验步骤:

答案

答:①烧杯中装入适量的水,用天平秤出烧杯和水的总质量m0

②用细线系住6个钩码,将1个钩码完全浸没在烧杯内的水中(未接触到烧杯底,且烧杯中的水未溢出),排开水的体积记为V0,测出此时的质量m1

③计算此时受到的浮力F1=(m1-m0)g;

④重复步骤②③,依次将2、3、4、5、6个钩码完全浸没在烧杯内的水中(未接触到烧杯底,且烧杯中的水未溢出),测出各次的质量m2、m3、m4、m5、m6,记录每次排开水的体积和相应的天平读数,并分别计算各次所受浮力F2=(m2-m0)g、F3=(m3-m0)g、F4=(m4-m0)g、F5=(m5-m0)g、F6=(m6-m0)g;

⑤求出各次所受浮力的比例关系,看是否为1:2:3:4:5:6,若是则说明浮力的大小与排开液体体积成正比.

阅读理解

阅读理解。

     A school party will be on Sunday Evening. The girls are talking about clothes.

     "I shall wear a black dress, so everybody will notice (注意) me," says Emily. "What about you,

Linda?"

     "I'm not sure. Maybe I'll wear jeans, an old skirt and a hat. People will notice me, too!" Linda

says.

      "What shall we do about the boys?" says Jane.

      "I hear that some of the boys learn to dance better this summer. Maybe it'll be better this time,"

says Mary.

      It is Sunday evening. Groups of students arrive. The music begins. The girls stand in a line on one

side, and the boys on another side. Mr. Green, their teacher, tries to get them together, but fails. After

a while Tim says, "I don't want to stand here the whole time. The party is only for two hours. It'll be

over soon." He starts to dance. All the others watches him. Then David asks Emily if she wants to

dance. Then Jack and Linda. Then, all begin to dance. Soon there are more dancers than watchers.

1. On Sunday evening, _________ will be held.

A. a birthday party                

B. a dance competition

C. a school party                  

D. a school meeting

2. The girls are talking about _________.

A. the party

B. their clothes for the party

C. the boys

D. how to dance in the party

3. When the music begins?

A. Tim says something.

B. Some students start to dance.

C. The girls stand in a line on one side and the boys on another side.

D. Groups of the students arrive.

4. What does Tim really mean?

A. Students should start to dance.

B. Students should stand the whole time.

C. The party would last two hours.

D. He will leave the party quickly.

5. _________ danced with Linda.  

A. Tim      

B. Jack    

C. David    

D. Emily

填空题