Block scheduled versus traditional biology teaching—an educational experiment using the water lily Christoph Randler Æ Konstanze Kranich Æ Monika Eisele Received: 24 January 2006 / Accepted: 13 March 2007 / Published online: 3 April 2007 Ó Springer Science+Business Media B.V. 2007 Abstract In this study, we compared a traditional teaching sequence (four distinct les- sons) with a block schedule dealing with the ecological adaptations of the water lily. The educational unit contained original plant material and both experimental groups received the same tasks and working sheets. Pupils worked together in groups of three to four pupils in a self-regulated manner, carrying out hands-on experiments. However, both groups differed in their time schedule (four distinct lessons of 45 min versus one block of 180 min). Pupils from the traditionally scheduled education performed significantly better in the immediate post-test while these differences merged in retention. Keywords Achievement Á Biology teaching Á Block scheduling Á Gender Á Weekly lessons Á Water lily Introduction During the last decade of the previous century, biological education has shifted towards science education in the federal State of Baden-Wuerttemberg (SW Germany). Nowadays, methodological skills and experiments are highly emphasised in the new curriculum. Pupils are engaged in a variety of hands-on, student-centred and self-determined learning schedules and are obliged to present their results either in the classroom, for example by a poster demonstration or an oral presentation or even within the public of the school. Within this new curriculum, lab-work tasks have received a special importance. The effectiveness C. Randler (&) Institute of Biology I, University of Leipzig, Johannisallee 21-23, Leipzig 04103, Germany e-mail: randler@uni-leipzig.de K. Kranich Á M. Eisele Institute for Natural Sciences and Technology, University of Education, PH Ludwigsburg, Reuteallee 46, Ludwigsburg 71634, Germany 123 Instr Sci (2008) 36:17–25 DOI 10.1007/s11251-007-9020-y