由於國中階段的學生在學習浮力概念時常遭遇困境，不僅學生感到吃力，
甚至，教師也學得難於施教。以往科教研究者探討學生科學習大都以認知
心理學從事科學概念研究發展。本研究嘗試假設學生在社會機制的制約下
，探討學生科學習的形成機制，採用胡賽爾現象學本質理念為基礎，配合
後實證哲學理念及社會認知建構觀點之研究方向。由理論架構設計以密度
、壓力、體積三種不同題型的學生樣本及資料編碼系統，透過紙筆測驗群
（373人）的資料分析結果,期望得到以現象學本質方法經由三組不同面相
密度、壓力、及體積型學生之建構浮力理解的心智模型。研究結果如下幾
點:（一）學生使用三種科學典範 知識密度、壓力、及體積概念進行推理
思考時，約30%可意識到選用科學典範知識加以推理詮釋，其餘70%學生則
未能。（二）作答密度、壓力、及體積題型的學生在推理過程分析，發現
主要有四個模型：1.描述述情節2.排序情節3.法則不正確符合邏輯推理4.
法則正確符合邏輯推理並且四個模型的比例分佈值將視不同問題情境而變
化。（三）三組學生在建構浮力知識的推理狀況，呈現出不同的表現：1.
甲卷密度型:學生在遭遇丁卷矛盾的情境下，學生表現出會有知識轉移的
現象，使日常生活語言推理呈現15%的正確性。但使用科學語言推理的變
化不明顯。2.乙卷壓力型:在日常生活語言犯錯的比率增加20%；科學語言
犯錯比率增加7%，其餘不明顯；能正確使用科學語言由45%下降為20%減
少25%相當突出。3.丙卷體積型:在日常生活犯錯增加20%，其他不明顯。
本研究從現象學本質方法診斷學生從密度、壓力、及體積三種不同面向，
來探討學生建構浮力理解的心智模型，研究結果發現，一方面，學生意識
到使壓力概念來詮釋浮力現象最佔優勢，其次是使用密度概念，最後是體
積概念。另一方面，學生使用知識概念的推理過程分析得知，以密度概念
達成目標者佔優勢，其次是體積概念，最後是壓力概念。

This research tries to investigate the formative mechanism of
learning of science under the control of social mechanism,
using Hussel's nature of phenomenology as a basis, also the
point of view of post-positivism and cognition of society. On
the basis of theoretical structure, we devise three types of
quetionaire, density, pressure and volume of student samples
also information coding system,via an analysis of a writing
test(373 people), we hope that we can get the the psyc-
hological model of buoyancy concept of the students in terms of
the ways of density, pressure and volume in nature of phenomen-
ology method. Our results are as follows:(1) 30% of the
students using three kinds of scientific paradigm density,
pressure and volume to deduce do realise to choose a scientific
paradigm knowledge to adeduce and interpret.the other 70% are
do not.(2) The three groups of students formulating buoyancy
concept show different characteristics 1. quetionaire A density
type: confro- nting the contradiction of quetionaire D,these
students show the conversion of knowledge deduction by the
ordinary usage of langu- age gives 15% of acuracy. but the use
of scientific language to deduce is not obvious.2.quetionaire B
pressure type: mistake in ordinary language usage increases
20% more mistakes of scienti- fice language increases 7% more,
the others are not obvious; pe- rcentage that applies the
scientific language correctly drops from 45% to 20%, a lowering
of 25%.3.quetionaire C volume type: mistake in ordinary
language usage increases 20%, the others are not obvious.(3)
Analysing the deducing process of students by types of
questionaire density,pressure and volume. We discover four
types of model:1.describing the situation 2.ordering the
situation 3.the rules are wrong,but it is of logical type.4.
the rules are correct, also logical the proportion of the four
models depend on the types of question.
This research tries to investigate the formative mechanism of