The timing of an experiment in the laboratory program is crucial for the student laboratory experience: acylation of ferrocene as a case studyElectronic supplementary information (ESI) available: Assessment criteria for this experiment from the originating institution at the time of this study and the ACELL educational analysis. See DOI: 10.1039/c3rp00011g

An assessment of the acylation of ferrocene laboratory exercise across three successive years resulted in a significant fluctuation in student perception of the experiment. This perception was measured by collecting student responses to an instrument immediately after the experiment, which includes Likert and open-ended responses from the student. Students in all three years identified technical benefits from the experiment. In Years 1 and 3, students also recognised the benefits of improving their conceptual understanding of organic chemistry. However, in Year 2, where background knowledge became a critical and limiting factor, all perception of conceptual understanding as an experiment objective was lost, and only recognition of technical development remained. Analysis of these data also indicated that students who have enough time to complete the experiment also perceive a measure of responsibility for their own learning, whereas time-poor students have an over-reliance on the laboratory notes and demonstrators. Addressing concepts such as these may be the triggers required for time-poor experiments to garner a positive student experience and maximise both the conceptual and technical benefits of the experiment.