This research aimed to compare the short and long-term effects of technology-supported and inquiry-based teaching prepared within the scope of energy transformation on students' academic achievement. It was designed as an exploratory action research case study. The research group consisted of forty-three students studying at the seventh grade (between thirteen-fourteen ages) of a public middle school in Turkey during the fall semester of the 2017 year. One of the classes with a similar academic background in the school where the researcher also worked as a science teacher was assigned as the experimental group and the other as the control group. The activities in the experimental group were carried out in a technology-supported manner using PhET simulations supported by also worksheets, while the control group was taught based on inquiry-based hands-on laboratory activities by worksheets. The data were collected through an achievement test consisting of open-ended questions and scoring with a rubric. The test was implemented twice, after the interventions, and in the following sixth month for both groups. Normally distributed data were compared with interdependent and paired-samples t-tests. The results showed that although the achievement scores for the technology-supported teaching group were significantly higher in the post test, no difference between the scores at the end of the sixth months, and significant information losses were experienced in both groups, with the most technology-supported science teaching.