[en] Video is becoming one of the main pedagogical tools nowadays. They are very common, mainly in Massive Open Online Courses (MOOC's), but also in virtual universities and more every day in blended and face-to-face learning. The increase of video importance can be related to several technological changes: 1) smartphones have brought high definition cameras to the hands of everyone, 2) faster home internet connections allow sharing heavy files like those of videos, and 3) YouTube and Vimeo among others, have made it easy to upload and view videos. Therefore, nowadays video is a common way of consuming information and has become a natural way to get new knowledge. All these changes have become a video evolution since: 1) before the smartphone era, videos were a unidirectional channel of communication: the creator of the video (active), and the consumer (passive). Although we could make comments, the video itself was not enriched by those comments, like can be done with documents. It could not even be enriched with extra information, like the mechanisms allowed by hypertext. 2) Not everybody could create videos since cameras; hardware and software for editing were expensive. However, nowadays, this situation has changed. Now everybody with a smartphone create acceptable quality videos. Some smartphone's operative systems even have powerful video editing software. On the other hands, computers now have screen capture and desktops and tablets have become a common everyday tool. This new scenario is especially convenient for virtual environments like that of Universitat Oberta de Catalunya. Sometimes it is difficult to ask or answer something only by a text or a document, but it is easier explaining it through a desktop capture video from a tablet. Therefore, is has become more common everyday that teachers and students use video as a tool of communication. Nevertheless, although video is important in any aspect of studies, it is especially important in science teaching, like physics. There, mathematics and complex concepts make communicating difficult. Video animations are a common tool in face-to-face, blended and virtual environments; but in virtual environments it is difficult to ask or answer a question by writing only. Thus, video plays a key role in science and engineering, specially, in virtual environments. However, it must be considered that video can include many different kinds of objects: animations, desktop captures, video recording, etc. Therefore, it is unavoidable that different questions can be raised, such as: Which kind of videos we found? What the advantages and drawbacks of every one of them are from the point of view of teachers and students? Which role does the time factor play in videos? Which are the more useful kind of videos in sciences? In the present paper these questions are answered. First of all a review of the kind of videos is developed, analyzing the advantages and drawbacks of every one of them. Then, a drawback has risen to a group of students and a deeper interview with two of them is carried on in order to know their perception. All these analysis are focused in a physics subject.

[es] El video se está convirtiendo en una de las herramientas pedagógicas principales hoy en día. Son muy comunes, principalmente en Massive Open Online Courses (MOOC's), pero también en universidades virtuales y cada día más en el aprendizaje combinado y presencial. El aumento de la importancia del video puede relacionarse con varios cambios tecnológicos: 1) los teléfonos inteligentes han llevado las cámaras de alta definición a las manos de todos, 2) las conexiones a Internet más rápidas permiten compartir archivos pesados ¿¿como los de los videos, y 3) YouTube y Vimeo entre otros, han hecho que sea fácil cargar y ver videos. Este nuevo escenario es especialmente conveniente para entornos virtuales como el de la Universitat Oberta de Catalunya. A veces es difícil preguntar o responder algo solo por un texto o un documento, pero es más fácil explicarlo a través de un video de captura de escritorio desde una tableta. Por lo tanto, cada vez es más común que los maestros y los estudiantes usen el video como una herramienta de comunicación. Sin embargo, aunque el video es importante en cualquier aspecto de los estudios, es especialmente importante en la enseñanza de las ciencias, como la física. Sin embargo, se debe considerar que el video puede incluir muchos tipos diferentes de objetos: animaciones, capturas de escritorio, grabación de videos, etc. Por lo tanto, es inevitable que surjan preguntas diferentes, como: ¿Qué tipo de videos encontramos? ¿Cuáles son las ventajas y desventajas de cada uno de ellos desde el punto de vista de profesores y estudiantes? ¿Qué papel juega el factor tiempo en los videos? ¿Cuáles son los tipos de videos más útiles en ciencias? En el presente documento estas preguntas son respondidas. En primer lugar, se desarrolla una revisión del tipo de videos, analizando las ventajas y desventajas de cada uno de ellos. Luego, se presenta un problema a un grupo de estudiantes y se lleva a cabo una entrevista más profunda con dos de ellos para conocer su percepción. Todos estos análisis se centran en un tema de física.