Information and Communications Technology (ICT) plays a dominant role in enhancing teaching and learning. Similar advances have been made in the use of multimedia in the classroom. These advances are coupled with newer developmental tools and techniques. This paper examines the design and development of a simulation on water conservation. Science concepts taught through traditional methods are brought to life through animation and multimedia. The paper examines the underlying instructional design and pedagogy for developing useful simulations. It also highlights the support provided by currently available authoring tools. The paper concludes with how the effectiveness of simulations can be examined, and discusses issues around the use of simulations and learning objects in the primary classroom. (Contains 17 figures.)