小时候,我常常听别人说起,有一种海,我们人、动物或其他生物等等,不管是多么重的任何东西,在这水面上,都不会沉下去,就算是不会游泳的人来说,都不会有任何的生命危险,反而还可以在水里悠然自得地躺在水中看报纸等东西。但我又听说过另一种海,曾经把许许多多的人所吞没,一根骨头都不剩,简直是九死一生。这到底是为什么呢?
根据父母的讲诉,我进一步的明白了为什么死海里,人可以悠哉乐哉的享受着,却不用担心生命安全,因为死海里含有大量的盐,根据网络的资料显示,我们明白了盐是一种人们日常生活中不可缺少的食品之一,它不仅增加菜肴的滋味,还能促进胃消化液的分泌,增进食欲,而且,它能够维持正常的渗透压及体内酸碱的平衡,同时盐是咸味的载体,是一种白色的调味品。这一点在我的实验中很快就得到证实了。
浓度不同的盐水,对物体的浮沉有影响吗?这是我们第二个实验的阶段。我先拿来三碗一样多的水放在面前,在往这三碗水分别倒上三种密度不一样的盐:第一碗放了一、两勺,第二碗放了五、六勺,第三碗放了九、十勺,再把鸡蛋放进这三杯盐水中,并观察鸡蛋在水中的位置。
这项实验的结果是:放了一、两勺的盐水中,鸡蛋是下浮,没有一点上升的现象;放了五、六勺的.盐水中,鸡蛋是悬浮在半水空中;再来看看放盐最多的杯子,整只鸡蛋的半身都浮现在水面上。
通过这次实验,我知道了浓度不同的盐水,对物体的浮沉是会有着不同的影响,对于不同的重力与浮力,位置也会是不同的。
我还了解到了,盐在人们生活中有着不可替代的作用,这是大家有目共睹的。举例来说,在我们烹制美味佳肴时,没有盐可不行;一个人如果长期不吃盐,就会有气无力;饲料中缺盐或盐的含量不足,会引起畜禽食欲不振,消化障碍,并养成异食癖。严重时,畜禽的精神不振,发育不良或体重下降所以,盐对人们生活是很重要的。在此,我呼吁全社会的人们好好地利用起它们,不能使它们遭受污染,不然,对全人类,对身边的坏境,对整个地球将会后患无穷,这真会是惨不忍睹。
Firstly,you can expand your knowledge by watching TV.As we all know,learning things by TV is much faster than by listening to the radio or just by reading books.For it has colorful pictures as well as wonderful music.
Secondly,you may know anybody you want to know such as famous singers,super stars,scientists and so on.
What’s more,you can go everywhere by traveling programs.Let’s suppose,if you like traveling very much,but you have to work on weekends or holidays,you must be very sad.And now open your TV and it’ll take you to anywhere.
Every coin has two sides.The disadvantages are also obvious.For example,watching too much TV can easily become short-sighted,especially for children and students.To make matters worse,some young students are keen on watching TV so that they give up their studies gradually.
Through above analysis,I think watching TV is a way of studying,it is good for us to watch TV.But when we watch TV,we should make a plan otherwise watching TV will destroy our life.
当然,也有健康优良的节目,像“国家地理频道”和“动物星球频道”,不但介绍动物的生活,还有人类未来发展的趋势,以及探险家的冒险过程,可以增广见闻呵!我很喜欢看动物的生活,还会拿出动物图鉴来对照,认识更多的动物。看到图鉴里形形色色的动物都“动”了起来,真的很有趣!虽然动物的世界也有残酷的一面,但是温馨的画面也是很感人的。
说到电视对我的影响,还是少不了我喜欢看的'卡通!虽然我已经快升初中了,却还是很喜欢看《哆啦A梦》、《神奇宝贝》、《小丸子》等卡通节目,可别笑我幼稚,这些可是我和小小孩谈天的好话题呢!
不过,跟同龄的朋友谈天时,就谈些最新的偶像剧、武侠剧,即使我很少看,还是会注意一下,要不然和朋友就搭不上线了。
电视对我的影响是很深远的,好节目让我吸收最新资讯,增广见闻,而不好的节目可能会使我学到坏榜样。因此,谨慎的选择节目是很重要的,而且千万别沉迷在其中哟!
the sun rises in the east and sets in the west, which is caused by the rotation of the earth as you all know. but have you ever thought of the effect of the earths rotation on man and can you imagine what would happen if the earth stopped rotating?
the radius of the earth is about 6,370 kilometres. it takes the earth 24 hours to rotate once. objects on the earths equator move with the earth at a speed of 460 metres per second, and the air close to the earths surface turns at the same speed. if the earth stopped rotating suddenly, the air would keep flowing eastward at a speed of 460 metres per second. the wind would be fourteen times as powerful as a hurricane. at the same time sea water would rush eastward at a speed of several hundred metres per second, which might do damages much greater than a seaquake would do. obviously, men could hardly stand such a catastrophe.
even if such a catastrophe would not happen, there would be a great temperature difference on the two hemispheres of the earth, and the four seasons of the year would no longer occur because a day and a night would be as long as a whole year instead of 24 hours. all this would greatly affect the life of human beings, imals and plants and that would cause worse results than anything imaginable.
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