Using animations is always very important for the effectiveness of digital learning materials. However, in this particular case, the quality of the animations is poor. The development of multimedia and interactive resources should be reviewed, in order to stimulate the meaningful learning. In addition to this, it is not clear the instructions for the navigation through the material. That is to say, it is necessary to show clearly how the students can use this learning tool and how to explore the animations. These instructions should not be only in the text, otherwise it is confusing to use the animations.