 Does the visualisation accurately represent our best understanding of the science?  Does it avoid confusing details and avoid reinforcing common misconceptions?  Is the visualisation of something students can already see, or of something invisible?  Are there alternative ways of visualising the same phenomena?  What evidence do students have of the accuracy of the visualisation?

 Is the visualisation simply presented alone, requiring you to plan a lesson around it?  Or is the visualisation embedded in support material such as lesson plans, worksheets, tutorials, student questions etc.?  (neither is necesssarily better, depending on your purposes)

 Does the visualisation engage students actively or have them sit passively?  (prior question – what is the goal of using it?)  Is it designed for a whole class setting, for one student to a computer, for several students to a computer? How can it be adapted?  How does it link to experiments and the ‘real world’?  How do students get out of it?

 Our goal is to teach physics:  Is the learning curve for learning to use the visualisation itself so steep that most of the learning in the lesson is the technical detail of the visualisation, rather than the physics concept?

 Does it look good, or is it painful to look at?  (remembering that (some of) our students are playing fantastic looking games and seeing amazing CGI movies)  Is it complex enough to do the job but simple enough not to confuse students?  Are the colours and shapes and other details chosen so that they communicate clearly?

 If you have students in your class with disabilities, does the visualisation cater to their needs, or can it be adapted to do so?  Can fonts be zoomed for students with reduced vision, and colours be changed for those who are colour-blind? Can text be read by a screen-reader for blind students?  Is sound essential, and can it be replaced with text for deaf students?

 Is it clear to students what they need to do to interact with the visualisation?  Are buttons and controls clearly labeled and do they follow conventions for navigation?  Is there a ‘Help’ icon that students can use if they get stuck? Is it really helpful?  Is the operation of the visualisation intuitive and easy to use?

 Will it run smoothly on the computers you have available? With a whole class using it?  Does it require a specific plugin that might be on your computer but not in the lab? E.g. Java, Flash, Quicktime, etc.  Will automatic backup systems remove it from the computers over night?  Does it require a specific install on each computer?

 You are the person who knows your own class and your own teaching style best – some visualisations will simply be a better fit for you and your students than others  This is a subjective judgement but an important one

 No visualisation is perfect  Finding the best one for a particular class is a matter of finding the optimum blend of all criteria  Some criteria are more important than others, e.g. scientific accuracy – it’s unhelpful if the visualisation creates new misconceptions!