For five years, future Spanish Navy officers must complete a Mechanical Engineering degree at the Defence University Centre in the Spanish Naval Academy, while focusing their training and efforts on becoming officers in the Armed Forces. Additionally, the interest of engineering students in fundamental subjects such as physics and mathematics has declined significantly.

In order to capture the attention and motivation of students in physics, we developed a teaching innovation project that aimed to diversify the methods used to explain the theory applied during problem-solving lessons. These methods include: conducting theory-related experiments in class; watching and discussing scenes from series and films; and using specifically designed, filmed and edited videos to explain difficult concepts.

In this paper, we present two short videos (filmed using webcams similar to those used by Instagram users) that explain the projection of a two-dimensional movement onto two different axes in Kinematics, a concept that can also be generalised to Dynamics. Although we explain that the ideal parabolic movement of an object thrown from the ground can be studied as two movements, usually one along the horizontal axis and another along the vertical axis, students only accept this as a mathematical resource and do not really understand it. When solving problems of relative motion using vectorial nomenclature, students often only see one equation, rather than one equation for each of the directions indicated by the unit vectors (i.e. one equation for each axis).

After showing two videos of two different movements and their projections (a two-dimensional linear movement and a parabolic movement) we asked the students about their opinion on the activity and we asked a question to evaluate the usefulness of the videos. Of 55 people that completed the entire activity (visualising the videos and answering the questions), nine people answered that it was not possible to describe the problems using axes in other directions. This shows the necessity of improving the activity possibly by expending some time discussing it after they answer the questions. Of the 55 students that completed the activity only two of them said that the videos did not contribute to their understanding of this subject.

We think that we can expand the use of this kind of short videos to support the explanation of other concepts difficult to visualise for some students within the subject of kinematics such as relative motion.

Keywords: Education, kinematics, video, webcam.