## 4 Discussion  
In the present work, two different technological solutions based on AR and VR were designed and developed in order to enhance the visit to a technological heritage museum and improve its didactic contributions. Furthermore, a study was conducted to evaluate the participant's experience associated with the AR-based visit. Technology should not be an end in itself; instead, it should be considered as a way to generate a better experience for the visitors, also contributing to their understanding and knowledge acquisition [16]. In the present work, the AR application was designed based on a detailed analysis of the museum artifacts to detect those that would be more suitable to be enhanced with multimedia content, including video, audio, or interactive images. In some cases, the multimedia content was used to provide additional information that could not be obtained from the traditional visit, such as videos that described how old artifacts work, or images to demonstrate different image processing methods over an image included in the exhibit. Using AR contents to show how an old device worked also contributes to the preservation of the original artifact without damage, which is an important issue for museums [55]. If the exhibit put the actual artifacts in operation, they would deteriorate quickly. However, if their working behaviour is shown using AR videos or animations, the artifact will not deteriorate and it will be perfectly conserved for future generations. In other cases, the multimedia content provides some contextual information, such as images from operators from different time periods that are shown close to a switchboard. This kind of additional content can also contribute to making the experience more enjoyable for the visitors. Most of the previous studies that validate AR experiences in museums are focused on the description and evaluation of the technologically enhanced experience without comparing it with the traditional one [1]. Only a few studies report comparing the AR-based experience with the traditional visit and with a reduced number of participants [12; 35; 40]. In the present work, 245 volunteers participated in the study and they were assigned to two different experimental conditions to allow the comparison between the traditional visit and the AR-based one. The participants' experience was evaluated by means of a questionnaire that they answered after having finished the visit, including Likert-like questions and open-answer questions. Globally, a significant association was found in the present work between the visit characteristics (traditional/ AR-based) and the visit outcomes, both regarding satisfaction and learning acquisition. Results show that it was more probable that participants reporteda high level of satisfaction after the experience if they performed the AR-based visit. A similar pattern was found regarding the learning acquisition during the experience, which was more likely to be positive if the visit was performed with the AR application. These results support the use of AR technology for this kind of experience. No signification association was found between the kind of visit and other evaluated factors, such as the preferred museum section. Focusing only on the evaluation of the AR experience by those participants that performed this kind of visit, it can be highlighted that most of the participants (more than 90%) reported positive satisfaction levels after the experience. Their comments in the open-answer question also show a positive evaluation of the application. They indicate some issues that could be improved in future versions, which are specially related to issues such as image quality, audio volume, interactivity, and hardware compatibility. These issues will be considered in future versions of the application, where more interactivity will be included and compatibility for other kinds of mobile operating systems will be added.