问题 填空题

密度测量:

(1)测定物质密度的原理是______.

(2)实验中用______来称物体的质量,用______来测量物体的体积.

(3)测定金属块密度的方法与步骤:

①______;②______;③______.

(4)测定液体密度的方法与步骤:

①______;②______;③______;④______.

答案

(1)测定物质密度的原理是密度的公式ρ=

m
V

(2)实验中用天平来称物体的质量,用量筒来测量物体的体积;

(3)测金属块密度时,应先用天平测其质量,再利用排水法,通过量筒测出其体积,最后用公式进行计算;

(4)测液体密度时,应先测烧杯与水的总质量,再向量筒中倒出一部分,测其剩余的质量,求出量筒中水的质量,读出量筒中水的体积,就可以代入公式进行计算了.

故答案为:

(1)ρ=

m
V

(2)天平,量筒;

(3)①用天平测出金属块的质量m;②在量筒中倒入一定量的水,读出体积V1;③将金属块浸入水中,读出量筒中的体积V2

(4)①测出烧杯与水的总质量m1;②将烧杯中的水倒入量筒中一部分;③测出烧杯与剩余水的质量m2;④读出量筒中水的体积V.

阅读理解

In the 60s, people asked about your astrological (about star) sign. In the 90s, they want to know your website.   1  Your website is an electronic meeting place for your family, friends and potentially, millions of people around the world. Best of all, you may not have to spend a cent. The web is filled with all kinds of free services and all it takes is some time and creativity.

 2 Like the table of contents of a book or magazine, the home page is the front door. Your site can have one or more pages, depending on how you design it.

While web pages vary greatly in their design and content, most use a traditional magazine layout(版面设计).At the top of the page is a banner(横幅). Next comes a greeting and a short description of the site. Pictures, text, and links to other websites follow.

 3 Think about whom the site is for and what you want to say. Next, gather up the material that you want to put on the site.

While there are no rules you have to follow, there are a few things to keep in mind:  4 If you are too much at the beginning, you may never get the site off the ground. You can always add to your site.

Less is better. Most people don’t like to read a lot of long text online.   5 

Smaller is better. Since it can take a long time to download large image files, keep the file sizes small.

Have the rights. Don’t put any material on your site unless you are sure you can do it legally. Always remember to get the permission from the writer first.

Now it’s time to roll up your sleeves and start building

A.Start simply.

B.Break it into small pieces.

C.Draw a rough layout on a sheet of paper.

D.Many websites are considered very interesting.E.Before you start building your site, do some planning.

F.Think of your home page as the starting point of your website.

G.These days, having a web address is almost as important as a street address.

判断题