科技论文1500字左右初中英语作文

With the development of science and technology， people's lives have been greatly There is no doubt that we benefit a lot from the scientific advancements in many different For instance， the invention of computers dramatically increases work efficiency and helps complete many difficult tasks that were impossible in the Apart from this， new discoveries and technology in medicine improve people's health， which allows them to enjoy a longer The progress of science also enlarges human's ablilities to explore the world around them， from up into space to deep under the Thanks to the development of science and technology， human society has enjoyed continuous prosperity and more However， just like a double-edged sword， science can cause problems It is known to all that the nuclear power， an environmentally friendly source of energy， can also be developed into a weapon of mass In addition， human cloning， which is expected to cure many serious diseases and save lives， may bring disasters of social As a matter of fact， most of the improvements in science are made at the cost of our precious natural resources and have done great harm to the environment where we live Therefore， how to deal with the progress of science and technology properly is worth our careful

The new century is It can be expected that there will be a breakthrough in life sceience and space science in the 21st First， scientists will conquer incurable diseases through the transformation of With the same technology they can breed new species of animals and even human life in the Most important of all， they can decelerate aging and prolong Besides， permanent stations will be set up in the moon or other planets or stars so that scientists can make a thorough study of the moon and other planets or Most probably life will be found in other stars in universe or the planets or stars suitable for the human existence will be However， the scientific development will also bring about some social How should we regard from an ethical perspective the one who is bred through the gene technology in the How can the police identify the criminal from a group of people with the same DNA? It is quite natural that we will meet problems in the scientific and social Therefore， we should be prepared to meet new 汇众动漫学院

我说，是科技的发展推动了人类的进程，是科技的发展才使人类有着这崭新又美好的生活。纵观千古，哪朝哪代不是重视科技的发展？科技发展是强国之路，科技发展是中华民族进步的第一动力，没有科学，我们哪来的今天的幸福生活？没有科技，我们哪来的舒适的物质生活与精神享受？没有科技的进步，我们哪能吃到杂交二号？我们哪能穿上全棉衣服，哪能住进高楼大厦？科技发展利大还是弊大？当然是利大！中华文明八千年历史文明就是铁证如山，历史每时每刻都在改变，科技每时每刻都在发展。如果是弊端大于利的话，那人类为什么都还不约而同的选择了进步？只有进步才能使明天更美好！一个人不进步是可悲的，一个国家不进步是没落的，一个世界不进步是黑暗的。只要在不断的进步中，人类的生活才可以得到升华。上天给予了人类一颗聪慧的大脑，一双勤劳的双手，人类没有坐享其成，而是选择了不断进步，几千年来，从马车变成了轿车、火车、飞机；从煤油灯变成了白炽灯、霓虹灯、节能灯；从海角天涯变成了近在咫尺、视频聊天、鼠标一点尽知天下事。所有人的不懈努力，刻苦钻研，我们今天的日子是有多少辛勤的科学家们用智慧甚至生命换来的。因为法拉第，我们生活的周围才充满了各种各样的电器；因为达尔文、因为孟德尔，我们才可以更好地了解自己，认识自己；因为扁鹊，因为华佗，因为李时珍，我们的生命才能得到保障。我们的平均寿命比古代提高了30岁，看望亲友甚至不用出家门，这不都是科学发展给我们带来的好处吗？所以说，科技改变历史，我们探讨科技的发展利大还是弊大是不需要质疑的，因为就是利大！利大！利大！科技改变历史，是科技发展救了我们，是科学把我们从水深火热的年代拯救了出来。科技改变历史，知识改变命运。我们跨入了21世纪，跨入了一个充满高科技的时代。科学改变了我们的生活，科学改变了我们的命运。“ 科技发展利大于弊，这是一个亘古不变的主题！

A Flow Shop with Compatibility Constraints in a Steelmaking Plant* Abstract We present a scheduling methodology for applications where the generation of schedules is constrained by antagonistic and vague Besides temporal and capacity constraints， compatibility constraints between consecutive jobs are We model the vague constraints and uncertain data by fuzzy set The importance of single jobs and the difficulty to schedule them is defined on the different constraints and is used to control the generation of A preliminary schedule is generated by considering the important jobs and those that are difficult to schedule Easy or not so important jobs are scheduled Finally， the achieved schedule is “repaired” until a schedule is found that achieves a given level of Since the goodness of solutions is rated by fuzzy sets， robust schedules achieve better evaluations than weak However， if no robust solution is found constraints will be This methodology is appropriate for applications in process engineering where uncertain knowledge is We explain the methodology with a case study from a steelmaking plant for high-grade steel 补充： Bidding for the Olympic Games， in a way， an image-creating The first and foremost thing is to let people fall in love with the city at first sight， attracting them by its unipue What image does Beijing intend to create for itself once it has the opportunity to host the 2008 Olympics? It is known to all that the Beijing Municipal Government has already set the theme for the future games: New Beijing， Great O For me， the 2008 Olympics will be a great green Olympics illuminated with two more special colors， yellow and First， yellow is a meaningful The Yellow River is China's Mother River and the descendants of the Yellow E This color has a special origin and great significance for the Chinese Beijing is the capital of New China and previously the capital for nine dynasties in Chinese So， yellow will naturally add splendor to the 2008 G Secondly， the 2008 Olympics will be a red Red is another traditionally cherished color for the whole We adore On big occasions， we like to decorate our homes in It is the color of double happiness， representing joyous moments， auspiciousness， enthusiasm and Red is one of the most suitable colors to describe the future of Beijing Beijing ， together with the whole country， is becoming more and more prosperous in the process of Should the 2008 Olympics be held in Beijing， the whole city will be a sea of red : the red torch，red flags， red flowers， and the radiant faces of millions of joyful Above all， the 2008 Olympics will be a green O Adding a green ingredient is essential in creating an appealing image， as we can't deny the fact that Beijing， at the moment， is not as green a city as what we like it to Striving for an environmentally appealing city has become a central task for all the citizens of B Big efforts have been made in pollution control， replanting and beautification of the According to a project entitled" The Green Olympic Action Plan"， between 1998 and 2007， Beijing， we have invested 100 billion RMB in preserving and protecting the Some 5 million trees and over 1 million acres of grass will be planted along the Fourth Ring R By then， the city's green area will make up 40% of its The city will also dredge its reservoirs used as a water supply to Beijing residents， controlling industrial pollution and moving out the 200 factories presently located within the city Certainly， all of this is no easy But I am sure that all of us have confidence that we will realize these green For now we have the full support and participation of the environmentally conscious Each citizen is showing great concern for every one of the steps the city government As the saying goes， United， we stand， and a green Beijing will be When our aspiration becomes a reality， it will be a unique O" New Beijing， Great Olympics"; will be weaved of these three superb colors: yellow， red and 追问：用中文写清楚这篇英文文章研究的是什么问题?这个问题是怎么研究的?发现了什么?这些发现意味着什么? 谢谢回答：第一篇与电有关求采纳

科技论文1500字左右初中英语

PrefaceThe ARPANET – the Department of Defense network that is the ancestor of today’s Internet—was built in the late sixties using a proprietary protocol This first protocol proved to have shortcomings for linking with other networks， which led to the development of Transfer Control Protocol/Internet Protocol (TCP/IP) TCP/IP used 32-bit address These soon proved to be unwieldy for most users， even when expressed in the less daunting formant of four 8-bit decimal numbers， delimited by The obvious solution was a scheme for addressing computers by After all， people relate much better to names and find it much easier to remember the computer in the corner as “Frodo，” rather than “”The First Generation: Hot TablesThe desire to refer to machines by name instead of number led to the first IP address management scheme: the host The host table is a file that contains all the IP address in use on a network， along with their The host table provides a mapping from a host’s name to its IP address， as well as reverse mapping: Given a host’s IP address， the user can look up its For a host table to be most user useful， it must contain the names of all the hosts with which a given host might want to For the ARPANET， that mean that the host table had to contain the names and IP address of every host on the Such a file was maintained by the Network Information Center (NIC)， the central organization responsible for managing the ARPANET The file was called HOSTSTXT and was similar in format to the/etc/hosts file on UNIX Network administrators all over the network e-mailed host table changed to the NIC every time they added or deleted a host or changed a host’s IP The NIC made the changes to its master host table， which it made available via File Transfer Protocol (FTP) Administrators periodically downloaded the latest version of the host table to stay

这个问题交给我，保证让你满意。你可以HI我。

这是《科学美国人》杂志上的《PLASTICS GET WIRED》Like many technological advances， the innovations in the field ofconducting polymers began by While attempting tomake an organic polymer called polyacetylene in the early1970s， Hideki Shirakawa of the Tokyo Institute of Technology mistakenlyadded 1，000 times more catalyst than the recipe called What he producedwas a lustrous， silvery film that resembled aluminum foil butstretched like Saran Wrap—something that sounds more like a new andimproved way to keep leftovers fresh than a potential breakthrough inmaterials The substance appeared so unusual that when Alan G MacDiarmidspied it， he wondered if it would be a candidate for his goal of making“synthetic metals”—nonmetallic substances that could transmit In 1977 Shirakawa joined MacDiarmid and Alan J Heeger in their laboratoryat the University of Pennsylvania to investigate this form of After mixing in some iodine， the group found that the material’sconductivity subsequently jumped by a factor of several Durable， cheap， manufacturable and flexible， conducting polymers inspiredvisions of a future of transparent circuits， artificial muscle and electronicdisplays that conveniently roll up under the Researchers haveauditioned various demonstration devices， including components thatcould be useful for new displays， such as plastic transistors and light-emittingdiodes (LEDs) Although such a future is about as dreamy as it gets，many investigators see broad marketing opportunities possible now—inantistatic coatings， electromagnetic shielding， lights for toys and microwaveovens， among Perhaps mundane， such applications are nonethelesspromising enough that universities are collaborating with corporations，and scientists have initiated start-Although the pace of technological innovation has been impressivelybrisk， whether the materials will have an effect on commerce remains Firms are unlikely to invest in new equipment if the devices performonly marginally better than existing Polymer-based batteries，for instance， have a longer shelf life than do conventional ones， but theyhave penetrated the market in only a limited Flat-panel displays andLEDs made of organic substances face entrenched competition from existinginorganic liquid crystals and Still， optimism pervades the Because plastic and electrical deviceshave become integral parts of the modern world， researchers are confidentthat at least some profitable uses will Conducting polymers constitutea radically novel market area， points out Ray H Baughman of Allied-Signal in Morristown， NJ， who predicts confidently， “Fortunes aregoing to be ”Polymers， the constituents of familiar plastic materials and syntheticfibers， are large organic molecules built out of smaller ones linked togetherin a long Generally， they are insulators， because their moleculeshave no free electrons for carrying To make these substances conductive，workers exploit a technique familiar to the semiconducting industry:doping， or adding atoms with interesting electronic Theadded atoms either give up some of their spare electrons to the polymerbonds or grab some electrons from the bonds (and thereby contribute positivecharges called holes) In either case， the chain becomes electrically Applying a voltage can then send electrons scampering over thelength of the 《MICROPROCESSORS IN 2020》Unlike many other technologies that fed our imaginationsand then faded away， the computer hastransformed our There can be little doubtthat it will continue to do so for many decades to Theengine driving this ongoing revolution is the microprocessor，the sliver of silicon that has led to countless inventions， suchas portable computers and fax machines， and has added intelligenceto modern automobiles and Astonishingly，the performance of microprocessors has improved25，000 times over since their invention only 27 years I have been asked to describe the microprocessor of Such predictions in my opinion tend to overstate the worthof radical， new computing Hence， I boldly predictthat changes will be evolutionary in nature， and not Even so， if the microprocessor continues to improveat its current rate， I cannot help but suggest that 25 yearsfrom now these chips will empower revolutionary software tocompute wonderful 《HOW THE SUPERTRANSISTORWORKS》Although it is rarely acknowledged，not one but two distinctelectronic revolutionswere set in motion by the invention ofthe transistor 50 years ago at Bell TelephoneL The better knownof the two has as its hallmark the trendtoward This revolutionwas fundamentally transformed in thelate 1950s， when Robert N Noyce andJack Kilby separately invented the integratedcircuit， in which multiple transistorsare fabricated within a single chipmade up of layers of a Years of this miniaturizationtrend have led to fingernail-size sliversof silicon containing millions of transistors，each measuring a few microns andconsuming perhaps a millionth of a wattin 如果需要更多跟我联系，我有pdf版的资料。

科技小论文1500字左右初中英语作文

写作思路：从文章的写作目的、中心主旨入手，以使文章中心思想鲜明、深刻地表现出来，正文：Modern technology makes life more convenient; Tools are milestones of scientific and technological progress and human Man used to saw trees with a hand saw， but now， a tree can be sawed down in a few minutes with a 现代科技使生活更加便捷；工具是科技进步和人类进步的里程碑。人类过去用手锯锯树，但是现在，用电锯可在几分钟内锯倒一棵树。Another example is more vivid: if you have something urgent to inform your friend， and his home is 2 hours away from your home， you may want to make a phone But there is no telephone in your friend's What should you do?另外一个例子更加生动形象：如果你有急事通知你的朋友，而他家距你家有2小时的路程，你可能想打个电话。但是你的朋友家又没安电话，你该怎么办？Nowadays， with the progress of modern science and technology， the use of internet has become very A few years ago， people had to search for a large amount of data to collect the required information， and finally they were exhausted and wasted a lot of Now， if you use the internet， everything will be a piece of As long as you tap the keyboard， you will be 如今，随着现代科技的进步，使用网络已很流行。若干年前，人们不得不查找大量资料来搜集需要的信息，最后人累得疲惫不堪，还浪费了大量时间。现在，如果使用网络，一切就都是小菜一碟了。只要轻敲键盘，就会有求必应。We all expect modern science and technology to reach a higher level， because modern science and technology really makes life more 我们都期待着现代科技能达到一个更高的水平，因为现代科技确实使生活变得更便捷。

As the modern technology develops，our life is becoming more and more However，with the demand of all kind of nature resources，pollution is becoming more Unluckily，this problem is linked to our modern There is no denying that technology bring comfortable living condition to We can drive to work rather on foot，and we can surf the internet，use our phones and buy anything with debit All kind of department is blinding in the In ancient time，it’s impossible for us to do these，but now we can do it，because our wisdom make a On other hand，many habitats has been destroyed become human being has being becoming more powerful with their new tools，while other animals can do nothing to stop What’s worse，if human apply nuclear weapon to defense themselves，it may lead to a destructive In a word，modern technology can not only make our life more beautiful but also destroy our And it depend on how we use

Nowadays， technology is everywhere around The development of technology has a significant affact toward the Several technologies that we usually use are the internet， computer， and These new technologies make our life much easier and First， the development of computer changes our Decades ago， people needed to do lots of complex calculation on hand because they did not have computer， and more obvious， they did not have the software for As the result of that， people spent hours on the equations that a computer can solve in just a Since the development of computer， people are able to use some kind of software to compute lots of complex functions and mathematical Computer becomes the most helpful equipment for the sciencists because they can use their time more In conclusion， I believe the development of technology brings significant impact to our It is very helpful to us and I believe technology will keep improving in

科技小论文1500字左右初中英语

科学发展观在飞秒瞬间判断派别的特征从泽维尔发现了"飞秒"这个最短的时间，从他因这一发现获得诺贝尔奖的那一刻，"飞秒"这个瞬间已被世界关注。人的一生中有无数个飞秒瞬间，无论任何事情，我们用国正论分出大小的过程，就是在那个千万亿分之一秒分成了两半。无论我们今天看到一个惊天动地的事件还是悲惨凄凉的形式，粗略地看待它们，好像是时间的煎熬，其实是经过飞秒瞬间之后，给予我们的感悟。让人无奈的是，我们感觉到的一切奇迹、遗憾或叹息都是经过了飞秒瞬间之后，才让我们看到。给我们这种奇妙的感觉，都是相对立的两方由飞秒瞬间穿越之后，它们的状态才固定下来。人们表现出来的爱与恨、情与仇、好与坏、美与丑、赞成与反对、欣喜与灾难，相互的确立和转换也都是在飞秒瞬间界定了派别。科学发展观作为一种文化，它和其他的文化一样表现出同样的性质。人们开始愿意接受的文化观点都是先接受了它们的表象，经过一段时期后，真正与主题基因发生亲缘似地互动时经过了那个飞秒瞬间，文化派别就这样被哲学确定了，派别的立场就成了分离不变性的"博弈实体"。《博弈圣经》中说过，两次直观才可进入实体，实体是国，可以从中剥离出无数的可能。由此得出结论，不经过飞秒瞬间看似融入主题的文化派别，也只是进入了一个空间单位，一半的行为仍是个人的性质，不能代表稳定的"博弈实体"。正因为实体文化的虚无性质，才需要根据主题要求，在飞秒瞬间进行分离，并吸收扩大文化派系，才能保持派别情感的实体特性。经过飞秒瞬间将主题的文化基因积累的爱融入科学发展观的实体基因里，那才是对科学发展观真正的爱。《博弈圣经》对爱这样陈述说："我们把文化进程中被瘾魂驱动的欲望抛弃了自我之后，自由给予的真、善、美，定义为爱。"这样一个个被唤醒的高官，他的行为有一种无私的爱，才是忠诚的骨干，就是一颗拥有魅力的野性种子；他会利用各种发起、召唤、倡导、指导的优质遗传特征，传播科学发展观的主题文化基因；他会改变一大片，这一大片里还会出现种子。聪明的文化基因，总是优先被唤醒，呈现出中心，它是防止自身衰变进行生物博弈的创新繁殖。这是我们从遗传学那里得到的启示。在连续的文化进程中，让他人接受科学发展观的文化，要靠多次的遗传交流才能逐渐地接近派别的飞秒瞬间。我们可以看出学习实践科学发展观的步伐很大，口号响亮，仍不见奇效，完全可以想象，唤醒人类在第三空地里的创新行为是与时俱进的发展历程。只有不断地对科学发展观的"一观二论"进行相互的红移轰击，喊多了，就变成了自我的内容，看到了科学发展观就像看到了自己的名字、影子。《博弈圣经》曾有一段描述："每一个人对自己的肖像和名字的敏感性，仍是存在一种神秘的知觉，因为无论什么人的生物特性都可以对实体影子和实体肖像产生神秘性，像把梦境看成实体知觉一样，有一定的实在性。" 科学发展观的"一观二论"一旦被接受，适用文化相对性，随时都可以跨越飞秒瞬间，分出真假文化派别，分出博弈的阵营，表现出感情，正像《博弈圣经》中说的："感情是依赖，是瘾魂驱动欲望过程中的殷勤创作。"如果不能依据国正论的哲学，在飞秒瞬间区别出大小（就是博弈实体与性质），就不能对科学发展观表现出感情，就不能信仰它那至高无尚的主题，也不能融入它的内容；即使在一个阵营也只是一种形式，一旦遇到困难，一半的可能性不会表现出感情忠诚和坚定实体的信念，内部将会出现消极、论争、障碍、麻烦和危险。任何虚假或不实在的表现，都是想用博弈的手段，战胜对方，独享支配权。科学发展观是领袖对战略文化的思考，是社会持续发展的纲领。在实践的过程中，文化只有一次次达成，文化没有成功，只有前行。每一个人都应该理解文明的永恒、普适、唯一性就是科学，再理解战略的连续性就是发展，发展就是创新，我们把大脑对科学和发展的抽象快照看成观念，这就是科学发展观的概念。我们无论走到哪里，都会受到科学发展观红移辐射的冲击。科学发展观是一个实体，任何一个实体都是一个博弈的平台，站在实体一边会占优。每个人都有机会竞争，竞争就是博弈，博弈的飞秒瞬间都是有输有赢。失败是博弈的结果，所谓成功也是博弈的庇护。

气垫船又叫“腾空船”，是一种利用空气的支撑力升离水面的船。这种船一出现立即受到全世界造船界的关注。　　　老师在三天前也叫我们制作气垫船，我兴致勃勃地拿出了制作气垫船的材料：光碟、101胶水、气球、瓶盖、吸管，开始准备做气垫船了。我一开始不会做，可是我们班的同学有很多都做好了，于是我决定试一试。　　　我班的同学做的样子都一样，可为什么有的跑远，有的跑近，有的跑快，还有的跑慢呢？我就一边思考着这些问题，一边开始操作，可是一开始不大顺利，连瓶盖都粘不到光碟上，我就请妈妈帮忙。瓶盖终于粘好了，刚好粘在光碟的正中央，我看起来很满意。下一步工作是用针把瓶盖钻一个小洞，可是我不会用力，一下子把手都扎破了，但是我忍着疼痛继续干下去，小洞终于扎好了。然后我把气球放在上面，大功终于告成了，虽然样子不是太好看，但是我现在兴奋不已，因为这是我自己完成的手工制作。接下来我很紧张，因为要开始试了，能否成功呢？不管怎么说还是试一试吧！我就用吸管向瓶盖眼里吹气，然后把吸管拿开，把它放在桌面上，一松手，气垫船跑起来了，终于成功了，我的气垫船虽不及真正的气垫船，但是，它也是形式上的气垫船，所以我很自豪。　　　通过这一次气垫船的科技小制作，我更加喜欢上了科学，所以我以后要加倍的努力学习，将来的一个成功的科学家。

科技论文1500字左右初中语文

就中国航天来说，每一次突破都来自于漫长的积累，而时间是衡量这种积累的刻度。东方红一号卫星1958年上马，1970年才发射成功，用时12年；神舟飞船1992年立项，1999年神舟一号无人飞船上天，2003年神舟五号才把航天员送上了天，用时11年。没有卫星、飞船和交会对接技术的成熟，就不会有空间站的建立。这一次次的积累和突破，才让我们能一次次为飞跃而自豪。今天的中国科技，已经写下很多“迟来的飞跃”。中国人进入太空、卫星探月、载人深潜器入海5000米……梦想正慢慢地一个个化为现实，补齐中国科技整体水平的短板。而这些，也必然为重大科技革命铺就基石。正是在这个意义上，科技革命或许还在远方，但梦想和智慧的双翼却已然鼓荡，寻找突破的脚步，每天都可以踏响。

中国的学生当不当自力、自强？答案是肯定的——中国学生应当学会自立自强。然而在实际生活中，有些中国学生却是懒惰的，依赖感十分强，他们在儿时依赖父母，在学习上依赖老师，在社会上依赖朋友。有个故事，说一个十来岁的孩子，一次与同学在外面吃饭，吃到鸡蛋时，他说这里的鸡蛋不好吃，和家里的不一样。问他怎么不一样，他说是太硬了，家里的鸡蛋是白皮的，很软，拿着就能吃。原来，他父母一直把鸡蛋剥了皮才给他吃。一个十几岁的孩子，竟连鸡蛋皮都不懂剥，这简直是个天大的笑话，然而事实却是如此，这孩子的自理能力实在太低了，难道我们不应学会自立自强，自己的事自己做吗？报纸上曾经有这样一则骇人听闻的消息：××名牌大学的一位优秀学生自杀了。究竟是什么原因让这位学习成绩优异的大学生自杀了呢？原来他是由于生活的困扰：不懂去买饭，不懂洗衣服，，不懂整理自己的房间……也许我们会觉得好笑，但放眼望去，又有多少孩子不懂自己洗衣服，不懂为自己做一顿饭，难道我们不应学会自立、自强，自己去做力所能及的事吗？有人活了十八岁，连吃一个桃子都不懂得自己洗，有人上了初中，生病连药都不懂自己买，更甚至有人读了三四年，书连书包都不懂整理，有人……他们只是一味的衣来伸手，饭来张口，他们就像高高在上的小皇帝，而他们的父母则是呼之则来，挥之则去的仆人，指东不敢往西，这些“小皇帝”真是够威风的了。我们常可以看到，外国的许多孩子的妈妈是一个“狠心”的妈妈，外国的许多孩子的爸爸是也“残忍”的爸爸。比尔盖茨，世界首富，然而他却将自己的财产捐献给自己的祖国，只留下那么很少的一点钱给自己的子女，并要求他们自己出去打工赚钱。外国妈妈看到儿子摔倒；毅然不去扶他，外国孩子向父母借钱，要写借条；外国孩子旅游，要去自己赚钱，而中国学生只要问父母就行了，这难道不是巨大的反差？愿天下的父母让自己的孩子学会自立、自强，愿天下的孩子们学会自立、自强。

科技小论文范文1：树干为什么是圆的在观察大自然的过程中我偶然发现，树干的形态都近似圆的——空圆锥状。树干为什么是圆锥状的?圆锥状树干有哪些好处?为了探索这些问题，我进行了更深入的观察、分析研究。　　在辅导老师的帮助下，我查阅了有关资料，了解到植物的茎有支持植物体、运输水分和其他养分的作用。树木的茎主要由维管束构成。茎的支持作用主要由木质部木纤维承担，虽然木本植物的茎会逐年加粗，但是在一定时间范围内，茎的木纤维数量是一定的，也就是树木茎的横截面面积一定。接着，我们围绕树干横截面面积一定，假设树干横截面长成不同形状，设计试验，探索树干呈圆锥状的原因和优点。　　经过实验，我们发现：(1)横截面积和长度一定时，三棱柱状物体纵向支持力最大，横向承受力最小；圆柱状物体纵向支持力不如三棱柱状物体，但横向承受力最大；(2)等质量不同形状的树干，矮个圆锥体形树干承受风力最大；(3)风是一种自然现象，影响着树木横截面的形状和树木生长的高矮。近似圆锥状的树干，重心低，加上庞大根系和大地连在一起，重心降得更低，稳度更大；(4)树干横截面呈圆形，可以减少损伤，具有更强的机械强度，能经受住风的袭击。同时，受风力的影响，树干各处的弯曲程度相似，不管风力来自哪个方向，树干承受的阻力大小相似，树干不易受到破坏。　　以上的实验反映了自然规律、自然界给我们启示：(1)横截面呈三角形的柱状物体，具有最大纵向支持力，其形态可用于建筑方面，例如角钢等；(2)横截面是圆形的圆状物体，具有最大的横向承受力，类似形态的建筑材料随处可见，如电视塔、电线杆等。　　在我的观察、试验和分析过程中，逐渐解释、揭示了树干呈圆锥状的奥秘，增长了知识，把学到的知识联系实际加以应用，既巩固了学到的知识，又提高了学习的兴趣，还初步学会了科学观察和分析方法。范文2：皮鞋为什么越擦越亮每到星期天，我总要完成妈妈交给我的擦鞋任务。告诉你，这可是我一星期零花钱的来源哦!拿到沾满灰尘的皮鞋后，我先把鞋面的灰尘擦掉，然后涂上鞋油，仔仔细细地擦一擦，皮鞋就会变得又亮又好看了。可这是为什么呢　　我找了同样牌子同样款式的新旧两双皮鞋进行对比观察。我先用手触摸两双皮鞋的鞋面，发现新皮鞋的表面比旧皮鞋的表面光滑得多。旧皮鞋涂上鞋油，仔细擦过后，虽然亮了许多，但仍无法与新皮鞋相比。皮鞋的亮度是否与鞋面的光滑程度有关呢?　　我取来一双没擦过的旧皮鞋，在放大镜下鞋面显得凹凸不平的。然后，我再在皮鞋上圈出两块表面都比较粗造的A区和B区，A区涂上鞋油并仔细擦拭，B区不涂鞋油作空白对照。我发现A区擦拭后，表面明显变光滑了许多，而且放在阳光下也比B区有光泽。为什么两者会产生这样的差别呢?　　我想到在物理课上老师曾经讲过：影剧院墙壁的表面是凹凸不平的，这样可以使声音大部分被吸收掉，让观众不受回声的干扰。同样道理，光线照到任何物体的表面都会产生反射，假如这个平面是高低不平的，光线就会向四面八方散射掉；假如这个平面是光滑的，那么我们就可以在一定的方向上看到反射光。　　皮鞋的表面原来就不是绝对的光滑，如果是旧皮鞋，它的表面当然更加的不平，这样它就不能使光线在一定的方向上产生反射，所以看上去没有什么光泽。而鞋油中有一些小颗粒，擦鞋的时候这些小颗粒正好可以填入皮鞋表面的凹坑中。如果再用布擦一擦，让鞋油涂得更均匀些，就会使皮鞋的表面变得光滑、平整，反射光线的能力也加强了。　　通过实验，我终于知道了皮鞋越擦越亮的秘密啦!范文3：醋对花卉有什么影响醋是生活中常用的调味品，花卉则能净化生态环境，并美化我们的生活。　　你是否想到过，醋和花卉有什么关系呢?我们怀着好奇心，开展了这个课题的探究。据富有种花经验的人告诉我们，对盆栽花卉施些醋溶液，可改善盆花的生长，增加花朵，而且花艳叶茂。这一点我们在实验中很快就证实了。　　浓度不同的醋溶液，对花卉有不同的影响吗?这是我们第二阶段的实验。我们选取长势相同的满天星、报春花、月亮花各四盆，分为四组，每组（三盆）各有三种花卉，分别编号、贴上标签。同时，我们取食用白醋配制成1％（pH值为2~3）、0．01％（pH值≈4）、0．0001％(pH值≈6)三种浓度不同的溶液，每天分别给三组盆花固定喷洒一种醋液，第四组盆花洒不含醋的清水。每五天观察记录花卉的生长情况。　　这项实验的结果是：喷洒低浓度醋液(pH值≈6)对这几种花卉没有明显影响；喷洒中等浓度醋液（pH值≈4）的花卉明显长得比其他几组好，花苞多，开花期提前，而且花色较浓艳，花期也延长了；喷洒pH值2－3的高浓度醋液后，反而使花朵过早凋萎。　　通过这次实验，我们可以告诉你：种花时适当喷洒一些醋液，可使花卉长得更好。不过要掌握好醋液的浓度，醋酸过浓则会伤害花卉。范文4：鱼会说话吗？您相信鱼会说话吗？这是一个耐人寻味的事，我想知道鱼是否会说话？我家买了两条小金鱼，一条是全黑的，黑的叫乐乐，因为它很快乐。一条红白相间的名字叫欣欣，因为它懂得欣赏，很好玩吧！他俩生活在鱼缸里，这个鱼缸可“非比寻常”。里面有山、花、树、贝壳、彩色石头……。很美吧！让我们一起来观察它！ 9月23日凌晨五点左右，我正要去喂食，我看见这么一个现象，我把鱼食撒到鱼缸里，乐乐吃了一点就不吃了。 9月23 日傍晚5 点15分，我看见鱼缸里的贝壳反过来了，小欣欣看见了，好像以为它——这个小贝壳要死了，连忙游过去，用它的头去抵，抵了近三、四分钟，它就不抵了，它游到乐乐旁边，用自己的尾巴扫了扫乐乐，然后互相碰了一下头，乐乐和欣欣一起游过去，把那块贝壳一起弄回原样了，这一点证明了“团结力量大”。通过两次的观察，让我知道了人类有人类的表达方式和交流语言，动物也有自己王国的表达方式和交流，这也告诉了我们，如果你不团结，那么你将一无所有，朋友之间的友谊真伟大。同时，我们也要多观察，多发现，但是不能因为你在动物身上作试验，就伤害小动物，因为动物是人类的朋友。范文5：蚂蚁为什么不会迷路？蚂蚁，相信大家都很熟悉。那又有谁能真正地了解蚂蚁呢？蚂蚁为什么不会迷路呢？带着这个问题，我查阅了一些书籍。书上说，蚂蚁从蚁穴出发到达目的地后，沿途会留下一些气味，返回蚁穴。用触角相互碰一下，通知其他的蚂蚁。科学家曾经就这个问题作了一个试验。科学家先确定一只蚂蚁，将他沿途到达目的地的地方用力擦干净。当这只蚂蚁返回时，在被擦去气味的地方突然间停了下来。原地边转圈边寻找着什么。从而得到蚂蚁是靠气味来辨别方向的。我为了证实这个结论，我做了个试验。我首先准备了一个十厘米左右的细小树枝，在树枝的一头放上一个诱饵——小糖果。我把这个装置放在一个蚁穴附近。不一会儿，有一只蚂蚁出来探路了。我把他引上木棍后，他到达了糖果的地方，仿佛在闻一闻、嗅一嗅。我趁此机会将木棍的中断部分截下一厘米的木棍。当这只蚂蚁返回的时候，就在被截去的地方左转右转，就是找不到回家的路。过了一会儿，我又重复了上面的试验，蚂蚁仍然没有找到回家的路。通过这两次实验，我终于知道蚂蚁为什么不会迷路的秘密了。原来蚂蚁是根据气味来辨别方向的。知道了蚂蚁的这一秘密后，我在想：是否我们可以制作一种蚂蚁报警器呢？当蚂蚁走到报警器附近时，报警器就能“闻”出蚂蚁的气味，然后发出鸣叫声，让我们知道蚂蚁跑到橱柜里了或其他地方。