Models are an important tool in science: not only do they act as a convenient device for describing a system or problem, but they also act as a conceptual tool for framing and exploring hypotheses. Models, and in particular computer simulations, are also an important education tool for training scientists, but it is difficult to teach students the value and use of models as a conceptual tool in their own right. Within the applied and whole-organism biological sciences, students often enter their courses with little trust of their mathematical abilities, and teaching them that scientific models are tools that they can engage with themselves is arguably a difficult task (especially given limitations in curriculum time and prior background knowledge). Here, I describe a half-day practical session designed to introduce modelling concepts to undergraduates on an applied biology course. This practical follows a progression from observation of a natural phenomenon (flocking behaviour in animals), to hypothesis formation, and then simulation of these hypotheses using a mixture of physical activity and individual computer work using agent-based models. Discussion focuses on why physical activity may be important for the students to be able to properly understand and appreciate the computer simulations.The various disciplines such as ecology, zoology, botany, conservation and experimental psychology that could be classified as 'whole organism biology' moved on from being just 'natural history' subjects to full-blown hypothesis-driven science when evolution was first formally acknowledged as a fundamental process behind observed phenomena (Darwin, 1859). Conceptually, these subjects rely on a rich range of hypotheses explored as mathematical 928 9582 ACKNOWLEDGMENTS SAR acknowledges the comments and feedback of the undergraduates who conducted and guided the development of this practical in 2006-2010, and would like to thank Heather Whitney and several anonymous reviewers for comments on the manuscript.