Experiments and observations on phase changes of water are an important part of primary school students’4th grade science studies. Through these phase change experiments a process called ‘super cooling’ often occurs. Due in many cases to a limited understanding of this cooling process, teachers often feel ill equipped to explain the science clearly to their students. In this paper we report on the results of some liquid to solid phase change experiments with water. We then discuss ways of improving the teaching and learning of this important part of the science syllabus.