engleski

Understanding of photosynthesis concepts related to students’ age

In Croatian schools, the complex photosynthesis concept is presented several times during primary and secondary school, each time with more detail. The problems in understanding photosynthesis processes are known from many previous studies and our own research ; thus we aimed to investigate how the students’ understanding of the basic photosynthesis concepts increases during the schooling period, and is it enhanced by gradual introduction of new contents. The present study was conducted on 269 students from 6 schools and 35 students preparing to be biology teachers. To test the students’ conceptual understanding, we implemented a question about the trends of O2 and CO2 gas concentrations during the night, which was expected to lead students to a correct explanation of photosynthesis, including the issues of the plants’ respiration and the absence of photosynthesis. Students of all age groups gave mainly incomplete explanations. The best result was achieved by the youngest participants in the age of 11, who have relied on the freshly acquired and well trained, but reproductive knowledge. Older students’ answers (aged 15, 17 and 22), which include more detail about the light-dependent and light-independent reactions, suggested that they developed misconceptions such as the belief that “oxygen is produced in Calvin cycle during the night” and that “CO2 converts to O2”. Student's explanations indicate the consistency of their understanding of the process, which does not change with gradual introduction of new contents as they are older. The observed misunderstanding could be linked to the cumulative introduction of the complex theoretical contents, but excluding research- based learning, as well as to inadequate time dedicated to establishing connections between students’ pre-conceptions and novel information. Our research results might be a strong argument supporting the upcoming change in the national curriculum.

photosynthesis; conceptual understanding; age groups

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