探究電腦多媒體教學對於國三學生學習酸鹼概念與概念改變之歷程

Abstract

在科學的課程中，酸鹼概念是相當重要的科學概念，本研究的主要目的在於探討我國國三學生在使用有關酸鹼鹽概念的電腦多媒體教材教學後，其對於酸鹼鹽概念之理解程度、迷思概念及心智模式的類型之改變情形。本研究中，採取了FLASH軟體製作動畫教材，呈現酸鹼鹽單元中抽象的概念，例如：酸性溶液與鹼性溶液的解離情形及中和情形，及酸鹼中和後的水及鹽類的水解情形，並維持教學內容的一致性。 研究對象是以台北縣某高中之國中部國三學生，隨機抽取出二個常態編班之班級共74人。研究重點以國中理化教材為主，統整其中的酸鹼鹽概念，建立重要的教學目標，據此完成電腦教學動畫及教學投影片，將教材分成A、B兩組實施，並採用二階段診斷測驗進行前測、後測、延宕測驗，亦在此兩組各抽取六人，於後測及延宕測驗時進行半結構性晤談，並根據所得的資料，找出學生的迷思概念及心智模式類型的轉變取向。 研究的結果發現：在後測與前測答對率的比較中，A組的學生答對率達顯著差異(p=0.012)；B組的學生答對率亦達顯著差異(p=0.000)，因此實驗教材的實驗可有效地提昇學生在酸鹼鹽單元中概念的學習。但在不同教材上的實施後，A組及B組之組間比較中，兩次測驗答對率的差異並未達顯著水準，也就是說，這兩份教材的不同並不影響學生學習的結果。在延宕測驗與後測答對率的比較中，A組的學生答對率未達顯著差異；B組的學生答對率亦未達顯著差異，因此概念變化的現象並不明顯。在後測六週後進行的延宕測驗，A組及B組之組間之答對率的差異並未達顯著水準，即表示教材的不同，不影響學生在教材實施後，其概念改變的情形。 在兩次晤談的結果比較分析，我們可以看到在不同的題型中，學生在後測訪談與延宕測驗之間的表現相當不一致，在中低成就的學生中，具有迷思概念維持或是迷思概念的型態發生改變的情形較明顯；在高成就的同學中，於弱酸及弱鹼之解離度變化概念、酸鹼中和概念、氣體溶解之酸鹼概念等相關題型中，亦具有迷思概念維持或是迷思概念的型態發生改變的情形。但無論同學們的成就如何，皆會發生迷思概念改變的情形。 在各項迷思概念類型中，其主要的心智模式如下：在溶液酸鹼性質單元有：現象模式、名稱-符號模式。在酸鹼混合單元有：強度模式、量的模式、電中性模式、名稱模式。在氣體溶解溶液酸鹼性單元有：溶液模式、壓力模式。在電解質解離單元有：解離度錯置模式、濃度模式及通電模式。在酸鹼強度與氫離子濃度的有：強度模式、量的模式、溫度錯置模式。在弱酸弱鹼稀釋單元有：恆定模式、體積改變模式、濃度模式、平衡方向錯置模式。The conception about acids and bases is important in the science curriculum. It not only closely relates to daily life and natural phenomenon, but also play a pivotal role in the development of chemistry history. The main purpose of this study was to explore the comprehensive level of our junior high school students after the instruction of the unit about acids, bases and salts by multimedia and animation. The change of misconceptions and metal models about acids, bases and salts were investigated as well. In this study, the abstract conception of the acidity and alkalinity was presented with the software, FLASH, such as the ionization of the acid solution and the base one, the neutralization, as well as the hydrolysis of the salts and water, after the neutralization. 74 junior high school students of 9th grade in two classes were sampled randomly from a local school in Taipei County. The study focus on integrating the conceptions in the units about acids, bases and salts from the textbooks for junior high school, and conforming the goals of the instruction. According to the above, the researcher designed the animations and the slides for instruction, and then the teaching aids were used in both group A and group B. Both of the groups took the pretest, posttest and extensive test which were constructed by the two-tiers questionnaire in sequence. 6 students from each group were interviewed individually right after the posttest and extensive test, and the results of the interviews represented the changes of the students’ misconceptions and mental models. The results of the study were as follows. In the comparison of the veracity after the posttest and the pretest, the veracity of the group A was at the significance level (p=0.012), and so was that of the group B (p=0.000). This showed us that the instruction could influence the conceptual leaning about the unit in both of the groups. But after using the different instruction sets, the comparison between the two groups was not at the significance level. In other words, the difference of the both instruction sets couldn’t affect the students’ learning. After the extensive test and the posttest, both of the groups’ veracity was not at the significance level. That is, the conceptual change was not obvious after the extensive test. The extensive test which was taken by both of the groups in the six weeks after the end of the posttest received that, the comparison between the two groups was not at the significance level. It indirectly showed that the difference of the both instruction sets couldn’t affect the extensive test. In the comparison and analysis of the records of two interviews, sampled students were not consistent in the different concepts. The maintenance of misconceptions and the change of the misconception type were obvious in the students of middle and low achievement level; but the students in the high achievement level had similar situation in some conceptions such as the ionization of the weak acids and weak bases to dilute, the neutralization of acids and bases, the conception of a solution dissolve gas either acidic or basic. But no matter what level the students’ achievement belonged to, the misconceptions always existed. In all of the misconception about the units, the main mental models were shown as follows. A phenomenon model and a name-symbol model in the acidity or alkalinity of a solution; a strength model, a quantity model, a name model and an electricity neutral model in the neutralization of acids and bases; a converse-ionization model, a concentration model and a galvanization model in the conception of a solution dissolve gas either acidic or basic; a strength model, a quantity model, a converse- temperature model in the conception of the strength of acids and bases and the concentration of H＋;and an immutable model, a volume model, a concentration model and a converse- equilibrium model in the conception of the weak acids and bases to dilute.