nowadays, we can see some boys and girls who live in a small world of their own. they bury themselves among books and are proud of themselves. they think that it will make them lose their face if they do housework for they often think themselves very noble.
these young people are wrong. in my opinion every student should have a knowledge of housework. after all, they will have a family of their own, and they should do their part in keeping a good home. boys should also learn to do housework, for what will they do if they remain single? though not all boys remain single,yet they will be very helpful in the family if they know some housework. anyhow they will not lose anything, but, on the contrary, they will gain something useful.
for what i said above, we can find some eamples of our fellow-students studying abroad. all young men do housework as girls do. someone would argue that we can employ servants. this is true.however, what shall we do if the servant leaves us and all things are left to ourselves? we just cannot leave our clothes as they are and let worms and ants eat them up. and what can we do it we go and study in a foreign country where servants are out our means to employ? we must work for ourselves. why not start to learn to do housework now or else it will be too late? everyone should learn to do housework. what do you think about my idea, boys and girls?
these young people are wrong. in my opinion every student should have a knowledge of housework. after all, they will have a family of their own, and they should do their part in keeping a good home. boys should also learn to do housework, for what will they do if they remain single? though not all boys remain single, yet they will be very helpful in the family if they know some housework. anyhow they will not lose anything, but, on the contrary, they will gain something useful.
for what i said above, we can find some eamples of our fellow-students studying abroad. all young men do housework as girls do. someone would argue that we can employ servants. this is true. however, what shall we do if the servant leaves us and all things are left to ourselves? we just cannot leave our clothes as they are and let worms and ants eat them up. and what can we do it we go and study in a foreign country where servants are out our means to employ? we must work for ourselves. why not start to learn to do housework now or else it will be too late? everyone should learn to do housework. what do you think about my idea, boys and girls?
i think students should share some housework with their parents. the reasons are as follows. first, doing some housework can enable the students to have some sense of responsibility. there is a lot of housework in each family. as a member of the family, each one should do his or her share. since a student is a member of the family, undoubtedly, he is of no eception. in the second place, doing some housework can give the student opportunities to get to know his parents better. by doing housework, a student will know how hard it is for his parents to go to work everyday while raising a
family. he will make even greater efforts in his study later on. finally, doing some housework can give the student a chance to do some physicaleercises. since the student has to sit studying most of the time, this is certainly beneficial to his health.in light of the above, i strongly recommend that those who are not in the habit of doing housework start doing some right now. your parents will be pleased and you will learn something from it.
这时我想起了一个笑话,大热天,一个财主躺在大厅里的凉床上乘凉,可是浑身还是汗流不止。他唤仆人来给他扇扇子。过了一会儿,他遍体凉爽,一摸汗水都没有了。财主奇怪地说:“咦,汗到哪里去了?”仆人指着满头大汗说:“老爷,汗都跑到我身上了。”
是啊,我的汗跑到哪里去了?为什么电风扇吹出的风是凉爽的呢?带着这个问题,我查找了书籍和网络,终于得出了答案。
原来,人的皮肤表面都是潮湿的.,尤其在天热的时候,我们会出很多汗。风是空气流动的现象,空气有温度,但是风是没有温度的。电风扇只能加速空气的流动,从而形成风,但是风却不是凉的。空气的流动会使液体挥发的更快一些,当风吹到我们的皮肤时,皮肤表面的液体就会挥发成气体,这样会带走一些热量。汗液的挥发把我们皮肤表面的热量带走了,我们怎么会不凉快呢?
为了验证这个道理,我和妈妈又做了一个实验。把一块干燥的铁块对着风扇吹,它的温度并没有变化。我们用湿布在铁块表面涂了一层水,然后再放到电风扇前吹。铁块表面的水很快挥发掉,而用手触摸铁块,可以明显感觉到铁块的温度下降了。因为液体的挥发带走了铁块的热量。
弄懂了这个道理,我很高兴。我又进一步明白了物体变化的三种形态。
物体有三种形态,分别是液体,固体和气体。比如说水,它的液体形态是水,固体形态是冰,气体形态是水蒸气。把水放在零度以下的地方就会变成冰,放在锅里煮就会变成水蒸气。而从冰到水和从水到水蒸气都会吸收并带走热量,所以才有了“下雪不冷化雪冷”的说法。
真是身边处处有科学啊!
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