共查询到20条相似文献，搜索用时 140 毫秒
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翟伟平 《中学生数理化(高中版)》2011,(3):10-10
化学是一门实验的科学，从近年来高考化学实验题型的发展来看，符合新课程理念的要求，过程与方法的考查是命题的趋势．因而化学实验方案的设计和评价显得更引人关注．实验的设计可分为定性设计和定量设计两大方面，定性设计包括物质的制备、物质性质的验证和比较、物质分离和提纯、物质的鉴别与鉴定．定量设计包括测定计算某一成分的纯度与含量以及确定物质化学式的设计等．本文从物质制备实验方案、物质性质的实验方案、物质检验实验方案三大题型进行探讨，介绍这些题型解法的一般规律． 相似文献
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介绍"晶体的常识"的教学设计思路,展现如何利用丰富的素材和实验来帮助学生理解晶体性质和结构之间的关系。主要设计两个环节:(1)通过浏览晶体图片和晶体生长的微距视频,结合两个创新分组实验"快速制备KNO3、CuSO4晶体""探究方解石与玻璃的各向异性",师生一起观察和体验晶体的性质,丰富感性认知;(2)从"不断敲击方解石碎裂后的固体形状"入手,结合科学史话和"阅兵方阵和蜂巢"这一类宏观事物,师生一起推测晶体粒子的排列模型,并尝试利用模型解释晶体性质,最后与科学图片进行比照,理解晶体结构与性质之间的关系。 相似文献
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一、知识结构二、基础知识要点（一）熔解和凝固1．定义熔解物质从固态变液态。（吸热过程）凝固物质认液态变固态。（放热过程）熔点晶体溶解时的温度。晶体不同，熔点不同。凝固点液体凝固成晶作时的温度。同一晶体熔点和凝固点相同。2．特点晶体熔解（凝固）时，吸收（或放出）热量，其温度保持不变。非晶体无一定溶点与凝固点。单位质量的某种晶体，在熔点时变成同温度的液体吸收的热量，叫做这种物质的熔解热。如冰的熔解热是80卡／克。3．条件晶体熔解条件：①温度达到熔点；②继续吸收热量。晶体凝固条件：①温度达到凝固点；②继续… 相似文献
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不同的载体和温度会对明矾晶体制备产生什么样的影响?通过一系列实验,明确实验条件对晶体生长的影响情况,优化明矾晶种和晶体制备方案。 相似文献
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溶解度曲线题是中考化学中经久不衰的传统题．这类试题通常是根据溶解度曲线判断物质溶解度的大小、温度变化时有无晶体析出、同温下不同物质的饱和溶液中溶质的质量分数的大小以及使某物质的饱和溶液析出晶体的操作方法等．2004年中考化学题为这类传统题赋予了新的模式，给教学指出了新的导向． 相似文献
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溶解度曲线反映了物质的溶解度随温度变化情况，它有其广泛的应用，现总结如下，供同学们在学习中参考。1．根据溶解度曲线可以查出物质在某一温度时的溶解度。2根据溶解度曲线可以由物质的溶解度查出对应的温度。3．根据溶解度曲线可以比较不同的物质在同一温度下的溶解度的相对大小。4．根据溶解度曲线的斜度大小可以比较物质的溶解度受温度的影响程度。5根据溶解度曲线可以确定混合物分离提纯的方法。6．根据溶解度曲线可以确定从饱和溶液中析出晶体的方法。7根据溶解度曲线可以比较不同的物质在温度降低时析出晶体的多少或在温度升高时… 相似文献
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This discussion is a review of experimental work designed to determine whether pictures have an effect upon the derivation of meaning from the text printed in children's reading materials. Many reading schemes emphasize the use of illustration, but for a number of different purposes ranging from the provision of a referent for a specific word, to the provision of' contextual support, and the generation of motivation for reading. Experimental studies of the interactions between pictures arid words in the cognitive system go some way to supporting three uses of illustration in (a) the provision of meanings against which the print may be compared, (b) in the development of an organized understanding of the meaning of the text, and (c) in the enhancement of subsequent recall. The danger of distraction arising from the pictures has also been investigated, and been found to lead to decoding errors in young children presented with one word at a time. An analysis of mutual interference effects between pairs of pictures and words leads to the conclusion that the cognitive representations of meanings arc organized in a semantic system common to pictures and words. Thus, any decoding errors due to interference effects are of more than local importance—they can affect comprehension and influence the stored representation. 相似文献
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王西军 《周口师范学院学报》2007,24(3):154-156
中国画的造型方式有别于其他画种,既不追求绝对的写实,又不主张脱离真实物象的过分夸张变形,而是力求在尊重客观对象的基础上,对形象进行适当的处理,使所表现的形象更加符合画家的主观意图,更加生动,更具表现力。“意象造型”是水墨写意画所采用的基本造型手段,也是中国画造型的显著特征。 相似文献
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艺术图片在多媒体教学环境下变的快捷、有效,教学内容也变的形象、直观、丰富而生动,有别于传统的教学模式.像声音、形体、光色等多种感官的课堂调动,引起学生的极大兴趣,取得不错的教学效果,展示了艺术图片的教学魅力. 相似文献
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Viktor Johansson 《Educational Philosophy and Theory》2018,50(1):61-71
This article explores how different philosophical models and pictures of learning can become dogmatic and disguise other conceptions of learning. With reference to a passage from St. Paul, I give a sense of the dogmatic teleology that underpins philosophical assumptions about learning. The Pauline assumption is exemplified through a variety of models of learning as conceptualised by Israel Scheffler. In order to show how the Paulinian dogmatism can give rise to radically different pictures of learning, the article turns to St. Augustine’s and Robert Brandom’s examples of language learning, and to general strands in scholarship on moral education. Dewey’s view of childhood immaturity and the problem of adult maturity are used as first attempt at a counter picture to the idea that learning must have an end. The article takes Dewey’s idea further by suggesting how the Zen-Buddhist idea of killing the Buddha and Wittgenstein’s method of destroying pictures work on the dogmatic focus on uses of ‘learning’ that assume ends. In conclusion, the article suggests three possible uses of ‘learning’—learning from wonder, intransitive learning and passionate learning—that do not assume that learning has or must have a teleological end. 相似文献
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6-aminopenicillanic acid (6-APA) crystals obtained under different physical and chemical conditions of the solutions may present different habits. The habits of diamond-shaped plates are desirable compared with other habits of 6-APA crystals. To obtain ideal 6-APA crystals, the effects of the mixed solvents and additives on 6-APA crystal habits were investigated. Ethanol or acetone was used as the organic solvent, and impurities existing in the ,6-APA purification process were used as the additives. 6-APA growth habits were changed when the concentrations of ethanol, acetone or phenyl acetic acid were increased to exceed their critical concentration. The observed results show that the dominant face on 6-APA crystals was identified to be , {020}, but the overall habit was controlled by the relative growth rates of the : 101 and {002} faces. Crystal growth rates and habits can be appreciably changed by specific adsorption of additives on crystal faces. In some cases solvent molecules can act in a similar way and may be regarded as bulk additives. The effects of additives and organic solvents on 6-APA crystal habits were the results of adsorption effect,which fitted the experimental results quite well. 相似文献
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Wolfgang Schnotz Thorsten Rasch 《Educational technology research and development : ETR & D》2005,53(3):47-58
New technologies allow the display of text, static visuals, and animations. Although animations are inherently attractive,
they are not always beneficial for learning. Problems may arise especially when animations modify the learner's cognitive
load in an unintended way. In two learning experiments with 40 and 26 university students, the effects of animated pictures
on knowledge acquisition were investigated. Some pictures displayed visual simulations of changes over time, whereas other
pictures could be manipulated by learners to represent different states in time. Results showed that manipulation pictures
had an enabling function for individuals with high learning prerequisites, whereas simulation pictures had a facilitating
function for individuals with low learning prerequisites. However, the facilitating function was not beneficial for learning,
because learners were prevented from performing relevant cognitive processes on their own. A careful analysis of the interrelation
between different kinds of cognitive load and the process of learning is therefore required. 相似文献
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将传输矩阵法(TMM)应用于一维光子晶体带隙和带结构方程,计算了介电常数不随频率变化和随频率变化的带隙和带结构,计算并说明了在有缺陷的情况下缺陷态(局域态)的存在. 相似文献
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同课异构作为一种教研模式,为教师提供了一个互动交流的平台。小学英语同课异构的三节教学案例的分析,及从多个维度进行的比较与研究,启迪广大教师：应用思维导图可优化教学设计,提高教学质量,促进学生全面发展。 相似文献
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Dominique Cavet 《Educational Media International》2013,50(4):211-218
Abstract As described in the different announcements made by Kodak, their PHOTO CD originally appeared as a product targeted at the general public. However, the purpose of this article is to describe the system which Kodak is going to produce and which is specifically directed towards professionals. This will be of interest to the educational system for its potential use of photographs and images. As well as its attraction for the general public and the professional, PHOTO CD is characterized by the following two important aspects: ‐ The system does not in any way affect the way pictures are actually taken; conventional films are used which are only transferred onto optical disks after being developed. — The pictures can be viewed equally well on an ordinary television, or on a compatible PC micro or Macintosh. PHOTO CD, then, seems to be a means of constructing picture banks which are available for editing. Recalling existing pictures poses no greater problem than integrating new pictures into the bank,” on the other hand, from the number of possible ways of viewing pictures, one can foresee quite complex use (multimedia or micro) as well as simple use (diaporama on a television). 相似文献
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随着数字图像技术的发展和摄影器材更新,图像的摄取、欣赏从上世纪中末期的高雅、娱乐享受衍变为现代人之间一种无需语言和文字、直观纪实互通信息和交流文化的一种方式。人们通过“读图”快捷方便地获取信息。本文就数码摄影在当今“读图时代”地位与作用进行一些探讨。 相似文献