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Asia-Pacific Forum on Science Learning and Teaching, Volume 16, Issue 1, Article 4 (Jun., 2015) |
Research Design
This is a phenomenological research design because it provides opportunities to explore, describe, and analyze the meaning of an individual lived experience (Marshall & Rossman, 2006) which herein are two of the integrated science process skills, namely formulating hypotheses and identifying variables.
Participants
Two hundred and five (205) senior students studying science teacher education at a state university in Turkey participated in the study. This study used a convenience sampling method. Convenience sampling uses the most available sample for analysis (Cohen, Manion & Morrison 2000:102). Senior students were chosen for the study because they have teaching experience and they would have acquired some science process skills by that point in their education.
Science Education in Turkish Preservice Teacher Education
Preservice science teachers in Turkey take science, science education and general education courses for their degree. Some of their science courses are General Physics, General Physics Laboratory, General Chemistry, General Chemistry Laboratory, General Biology, and General Biology Laboratory. General Physics, General Chemistry, and General Biology courses focus on theory, while General Physics, Chemistry and Biology Laboratories courses focus on practical experiments. The content of the laboratory courses is intended to parallel the content of the theoretical courses. However, which experimental techniques (e.g. closed-ended or open-ended experiments) are taught in laboratory courses is not specified and is up to the discretion of the instructors. During their four years in the education in the Science Education Department where this study was conducted, preservice science teachers mostly learned close-ended experiments.
Data Collection
In this study, data were collected through document analyses (Scenario-1 and Scenario-2), individual observations and individual interviews. Preservice science teachers were asked to teach formulating a hypothesis and identifying variables based on Scenario-3 & Scenario-4 and observed for confirmation. The gathered data were analyzed using both descriptive (Scenario-1 & Scenario-2) and content analyses (Scenario-3 & Scenario-4).
Scenario-1 and Scenario-2: The “Science Process Skills Test (SPST)” was used as the data collection instrument. SPST was adapted towards assessing the science process skills of preservice science teachers by Aydogdu (2006). SPST has two parts. The SPST is composed of 7 scenarios and 9 multiple choice items whose answers must be explained with reasons, and it has a 0.70 reliability level. In this part, there are 9 multiple choice items that require explanations in the first part and there are 7 scenarios ending with open ended questions. The 9 multiple choice items from the SPST were developed by Enger & Yager, (1998) and adapted into Turkish by Aydoğdu (2006). The scenarios were prepared by Aydoğdu (2006) after an examination of different researchers’ studies (Anonymous, 2006; Dana, 2001; Enger & Yager, 1998; Ergin et al., 2005). These seven scenarios were then sent to two academics, who are expert in science teaching. Aydoğdu (2006) stated that final revisions were made and used in the SPST after he received the academics’ comments regarding whether the scenarios include and assess the science process skills of teachers. The SPST is composed of questions that measure basic science process skills like observation, classification, measurement, inference, and integrated science process skills like formulating a hypothesis, identification and controlling variables, conducting an experiment, collecting data, and assessing and interpreting results. However, this study only examined preservice science teachers’ skills of formulating a hypothesis and identifying and controlling variables. Within the scope of this study, only two scenarios (Scenario-1 and Scenario-2) were used from the SPST.
Scenario-3 and Scenario-4: After administering the two scenarios (Scenario-1 and Scenario-2) mentioned above to the preservice science teachers, their responses were examined. On the basis of those answers, three preservice science teachers who determined both the hypothesis and the variables as correct, partially correct and incorrect (totally 9 preservice teachers) were selected. Later the selected preservice teachers were sent to real classroom environment in order to apply an activity containing Scenario-3 and Scenario-4 (prepared by researcher) for hypothesis formulation and variable determining skills to 7th grade students.
Observation data: Two observers watched and analyzed how the preservice teachers taught the activities (Scenario-3 and Scenario-4) prepared for hypothesis formulation and variables determination of 7th grade students in detail through the video records lasting for 45-minutes.
Interview data: Moreover, interviews were conducted with preservice science teachers who incorrectly identified both the hypothesis and the variables. In the interview, preservice science teachers were asked “What factors contributed to your incorrect identification of the hypothesis, dependent and independent variables?”, and their responses were analyzed.
Administration of Data Collection Instrument
Scenario-1 and Scenario-2:Within the scope of this study, only two scenarios were used from the SPST and, per the research question, the author tried to identify preservice science teachers’ skills of formulating a hypothesis and identifying and controlling variables through these scenarios. Although the two scenarios used in the study had different research problems, preservice science teachers were expected to use similar skills, such as formulating a hypothesis and identifying and controlling variables.
The two scenarios used in the study and the research question based on the scenario are given as an example below and the possible answers for hypothesis, dependent, independent and control variables that preservice science teachers were supposed to provide are given in Box 1.
Box 1: Two sample scenarios (Scenario-1 and Scenario-2) which were adapted by Aydoğdu (2006) from the SPST.
Scenario 1: Hasan and Ahmet are playing in a park. Ahmet releases marble down the slide. Hasan claims that if the marble is slid from a higher slide it can move faster. This debate causes the following research question. After reading the research question and hypothesis find the dependent, independent and control variables.
Research question: If marble is released (go down) from slides with different heights, how does its speed change?
Hypothesis: if the height of the slide increases, the speed of the marble increases.
Dependent variable: the speed of the marble
Independent variable: the height of the slide
Control variable: the size, type and surface of the marble, the surface and slope of the slide.
Scenario 2: Melisa is a highly curious 6th grade student. She notices that a lorry is scattering salt over the road on a snowy day. After the lorry passes Melisa’s house, she puts on her boots, hat, and gloves, and goes to the road to make an observation. From her observation she designs a research question for an experiment she carries out later. Find the hypothesis, in addition to the dependent, independent and control variables.
Research Question:If salt is added to ice what will happen?
Hypothesis: if salt is added to ice, the melting speed of ice increases
Dependent variable: .the melting speed of ice
Independent variable: Adding salt
Control variable: Amount of ice and ambient temperature, etc…
Scenario-3 and Scenario-4: Examples of scenarios (Scenario-3 and Scenario-4) included in the activities prepared for hypothesis formulation and variable determining to be taught to 7th grade students within the scope of teaching practice of preservice science teachers are given in Box 2.
Box2: The sample activities involving two scenarios (Scenario-3 and Scenario-4)
Scenario 3: Ahmet and Hasan release the marbles in their hands into flour from a certain height. Ahmet’s marble sank in the flour deeper. Which factors do you think were effective in the fact that Ahmet’s marble sank deeper? In order to find a solution to this problem, formulate appropriate hypothesis/hypotheses and test the experiment determining the variables.
Hypothesis 1: If the height from which the marble is released increases, the rate of the marble sinking in the flour increases.
Dependent variable: Amount of the marble sinking in the flour
Independent variable: Height from which the marble is released
Control variable: Mass of the marble, volume of the marble
Hypothesis 2:.If the mass of the marble, increases the amount of the marble sinking in the flour increases
Dependent variable: Amount of the marble sinking in the flour
Independent variable: Mass of the marble
Control variable: Height from which the marble is released
Designing experiment
Preservice science teachers release two identical marbles into flour from different heights, and later measure the amount of sinking of the marbles into the flour for Hypothesis-1. And for Hypothesis-2, preservice science teachers release two marbles with different masses from identical heights and measure the amount of sinking of the marbles into the flour.
Scenario 4: Mert and Arda race identical toy cars on an the inclined plane and Mert’s car wins the competition. Which factors do you think were effective on Mert’s winning the competition? In order to find a solution to this problem, formulate appropriate hypothesis/hypotheses and test the experiment determining the variables.
Hypothesis1: Speed of the toy car increases if the slope of the inclined plane increases.
Dependent variable: Speed of the toy car
Independent variable: Slope of the inclined plane
Control variable: The toy car, slope of the inclined plane, the place where the car is released
Hypothesis 2: If the material used for the inclined plane changes, the speed of the car changes
Dependent variable: Speed of the toy car
Independent variable: Material used for the inclined plane
Control variable: The toy car, slope of the inclined plane, the place where the car is released
Designing experiment
Preservice science teachers release the toy car without initial speed from identical points by increasing the slope of the inclined plane for Hypothesis-1 and measure the speed of the toy car (the way taken). And for Hypothesis-2, preservice science teachers release the toy cars without initial speed changing the grounds in the inclined planes with identical slope and measure the speed of the toy cars. Lather they test the hypothesis they formulate.
The qualitative data from documents and interviews were descriptively analyzed while the data from observations were subjected to content analysis. The descriptive analysis technique evaluates the data, creating themes for each question. The collected data were summarized according to predefined themes and interpreted. In descriptive analysis, the aim is to present gathered data in an ordered and interpreted way to the reader. For that purpose, the gathered data is first described systematically and clearly (Yıldırım & Şimşek, 2013: 256). In order to ensure consistency, another expert’s analysis was also done. The observational data were analyzed through content analysis (Miles & Huberman, 1994; Patton, 2002; Yıldırım & Şimşek, 2013), in which themes, which are not pre-determined, are generated from codes assigned to the whole data.
Trustworthiness of the Data
1. Ensuring the trustworthiness of the answers given to the scenarios
The qualitative data gathered from the scenarios was analyzed by two researchers and the consistency between the researchers was 0.83. Moreover, the two researchers discussed their differences and reached a consensus. Finally, all the data (205 preservice science teachers answered two scenarios so totally a hundred scenarios’ data were analyzed) were analyzed by two researchers individually and the fittingness percentage between the two researchers was calculated to be 0.92. This fittingness percentage is quite reliable (Miles & Huberman, 1994). In the calculation of the fittingness percentage, the formula suggested by Miles and Huberman was used (Fittingness percentage= Agreement / (agreement+ disagreement)).
Table 1 displays the initial differences between the two researchers concerning the response of the preservice science teachers to Scenario-1 and Scenario-2 and in an adjacent column displays how these differences were resolved.
Table 1. Initial differences between the two researchers concerning preservice science teachers’ responses to Scenario-1 and Scenario-2, how these differences were resolved.
Scenarios
Integrated Science Process Skills
Statements of Students
Initial Differences
Consensus Result
Field expert-1
Field expert -2
Field expert -1
Field expert -2
Scenario-1
Formulating Hypothesis
The speed of marble changes according to the height of a slide
Correct
Partially correct
Correct
Correct
Dependent variable
Marble
Partially correct
Correct
Partially correct
Partially correct
Independent variable
Friction
Partially correct
Incorrect
Incorrect
Incorrect
Control variable
The length of the slope
Correct
Partially correct
Correct
Correct
Scenario-2
Formulating Hypothesis
Salt melts the ice
Correct
Partially correct
Partially correct
Partially correct
Dependent variable
Salt
Partially correct
Incorrect
Incorrect
Incorrect
Independent variable
Ice
Partially correct
Incorrect
Partially correct
Partially correct
Control variable
Melting ice
Incorrect
Partially correct
Incorrect
Incorrect
Table 2 presents the final rubric for evaluating preservice science teachers’ answers to Scenario-1 and Scenario-2.
Table 2. Scoring rubric for preservice science teachers (PST) responses to the research questions of Scenario-1 and Scenario-2.
Integrated Science Process Skills
Categories
Indicators
Sample statements of preservice science teachers for Scenario-1
Sample statements of preservice science teachers for Scenario-2
Formulating Hypothesis
Correct
Appropriate both to the problem situation and the structure of hypothesis.
PST4:If the height of the slide increases, the speed of the marble piece will increase.
PST14: If the height of the slide changes, the speed of the marble will change.
PST7:If salt is added to ice it melts
PST39: The more salt added to ice the faster it melts.
Partially Correct
Appropriate to given problem but inappropriate to hypothesis structure.
PST29: The change in the speed of the marble according to the height of the slide.
PST37: According to the steepness of the long and short slide the speed of the marble changes.
PST23: Salt melts the ice.
PST11: Ice melts in the places where salt is scattered.
Inappropriate to given problem but appropriate to hypothesis structure.
PST33: The smoother the slide the faster the item slides.
PST22: If the slope of the slide increases, the speed of the marble piece will increase.
PST21: If the quality of the salt increases, the ice melts faster
PST12: The thinner the salt the faster the snow melts
Incorrect
Inappropriate both to the problem situation and the structure of hypothesis.
PST24: The marble does not slide faster as there is friction in the air.
PST13: The ratio between the distance and time.
PST27: Slipperiness on the road will be prevented
PST16: It does not cause sliding
Dependent variable
Correct
The dependent variable is both appropriate to the given problem and stated correctly.
PST8: The speed of marble piece
PST50: The speed of marble
PST8: Melting speed of ice
PST50: Ice melting
Partially Correct
The dependent variable is appropriate to the given problem but the statement is missing.
PST41: Marble
PST35: Speed
PST43: Ice
PST25: Melting
Incorrect
The dependent variable is inappropriate to the given problem or dependent variable is stated incorrectly.
PST15: Height
PST37: The length of the slide
PST20: Salt
PST29: Pressure
Independent variable
Correct
The independent variable is both appropriate to the given problem and correctly stated.
PST8: The height of the slide
PST50: The height of the slope
PST8: Adding salt
PST50: The amount of the salt
Partially Correct
The independent variable is appropriate to the given problem but the statement is missing.
PST17: Slide (Slope)
PST31: Height
PST26: Salt
PST36: Little/a lot salt
Incorrect
The independent variable is inappropriate to the given problem or the independent variable is stated incorrectly.
PST19: Marble
PST23: Friction
PST12: Ice/ Snow
PST30: Gloves
Control Variable
Correct
The control variable is both appropriate to the given problem and correctly stated.
PST8: the size, type and surface of the marble, the surface and slope of the slide
PST50: The place where the marble was left; Slope
PST8:The amount of salt and environment temperature
PST50: Quality of ice environment
Partially Correct
The control variable is appropriate to the given problem but the statement is missing.
PST7: The surface of the slope/Friction, surface of the marble
PST48: The place of the marble, slope of the slide
PST8: Ice
PST17:Environment
Incorrect
The control variable is inappropriate to the given problem or the control variable is stated incorrectly.
PST13: Items, speed of the marble
PST44: Wideness of the slope
PST26:Scattering salt, Melisa
PST48: melting ice /ice melting
2. Ensuring the trustworthiness of the observation data
Two observers watched and analyzed how the preservice teachers taught the activities (Scenario-3 and Scenario-4) prepared for hypothesis formulation and variables determination of 7th grade students in detail through the video records lasting for 45-minutes. The consistency between the two researchers was calculated as 0.88. The differences between the researchers were then discussed and a consensus was reached. After reaching a consensus, the observation data was individually analyzed by two researchers; the fitting percentage between the two researchers was 0.96. The reason for selecting two observers is to increase reliability of observation notes (agreement percentage). The aim of observing preservice science teachers is to support the skills in formulating hypothesis and determining variable in the Scenario-1 and Scenario-2.
3. Ensuring the trustworthiness of the interview data
After administering the two scenarios mentioned above to the preservice science teachers, their responses were examined, and their correct answer percentage was calculated. Preservice science teachers who misidentified both the hypothesis and the variables (n=58) were interviewed. Qualitative data gathered from the interviews was analyzed by two researchers; the consistency between the two researchers was calculated as 0.94. The differences between the researchers were then discussed, and a consensus was reached. After reaching a consensus, the interview data was individually analyzed by two researchers; the fitting percentage between the two researchers was 0.98.
