18.04.2023
The constructivist learning approach is an effective process for students to become aware of their misconceptions by actively constructing knowledge themselves. In the constructivist learning process, the teacher's role is to create a classroom environment where students can solve their own problems and make their own discoveries. In this process, teachers act as guides, ensuring students remain constantly active in the lesson through appropriate strategies. Many strategies have been developed for effectively teaching, learning, or evaluating any concept in science. The Predict-Observe-Explain (POE) strategy is one of the most frequently used strategies in the constructivist approach. In the POE strategy, students are asked to predict the outcome of an event in an activity prepared by their teacher, along with the reasons behind it. Then, students make observations of the given event. Finally, the relationship between the students' predictions and observations is explained, and any discrepancies are resolved. The aim in science education is not only to impart knowledge but also to develop strategies that will help students in the process of developing relationships between concepts and sub-concepts. The TGA strategy applied for this purpose has 3 stages: ‘Predict – Observe – Explain’.
Predicting Stage:
In this stage, students are given information about an event or experiment. Students are asked to predict the outcome of the experiment and explain their predictions with reasons.
Observation Stage:
The experimental setup given to the student in the prediction stage is set up, and the student is asked to observe the experiment and record their observations. The teacher acts as a guide in this stage to ensure students make accurate observations. Students record their observations according to the instructions given by the teacher.
Explanation Stage:
This is the stage where the concept is restructured. The relationship between the answer given by the students in the prediction stage and the data obtained as a result of the experiment is explained. If there are contradictions between the students' predictions and observations, these contradictions are discussed, and any misconceptions the students may have are corrected.
AN EXAMPLE OF A TGA APPLICATION:
The stages of the ‘Which Candle Goes Out First?’ TGA activity, conducted within the scope of the Chemical Reactions topic in the 8th Grade Matter and Industry Unit, are as follows:
Prediction Stage:
Students are asked the question, ‘If identical candles are lit at the same time and covered with two jars of the same width but different dimensions, which jar's candle would you expect to go out first? Why?’ and are asked to predict the outcome of the experiment with their reasons.
Example:
Student 1: ‘The candle in the smaller jar will go out first because it has less oxygen.’
Student 2: ‘The candle in the larger jar will go out first because there is more carbon dioxide in the air inside.’ The students' predictions are taken in turn. After all students' predictions about the experiment are received, the observation stage of the experiment begins.
Observation Stage:
In this stage, a student is randomly selected from the class to conduct the experiment. Students conduct the experiment using the materials provided by their teacher.
Observation of the experiment: Identical candles are lit simultaneously and covered with jars of different sizes. It is observed that the candle in the smaller jar extinguishes before the candle in the larger jar.
Students record the data they obtain from their observations in the experiment. The explanation phase begins, where the relationship between the data obtained from the experiment and their predictions is explained.
Explanation phase:
Students explain the relationship between the answer they gave in the prediction stage and the data they obtained as a result of the experiment.
Example:
Student: ‘Oxygen is needed in the environment for the combustion reaction to continue. Since the amount of oxygen in the air in the large jar is greater than the amount of oxygen in the small jar, the candle in the large jar extinguished later.’ Students are asked to explain their results from the experiment in this way.
Through this example TGA activity, students understand the importance of the amount of oxygen in combustion reactions; They learn through the predictions they make, the data they obtain from experiments as a result of their observations, and their explanations.
As mentioned in the activity above, the TGA strategy is a strategy frequently used by teachers in teaching science concepts, and it is an indispensable process of the constructivist learning approach, where students generate ideas and make inferences about the reasons behind the concepts while learning them.
Keywords: TGA strategy, constructivist approach, science education
