Primary school students will not recall a time before the advent of mobile technologies and the use of apps is likely to be part of their everyday lives at school and at home. There is a growing curiosity among students who want to create their own apps, rather than simply use apps created by others. New curricula and pressure from outside sources have prompted teachers to teach computational thinking skills to students. The benefits of students creating prototypes of apps to realise their conceptualisations and to enhance computational thinking skills are explored through a comparison of two examples of practice.