An analysis of the use of augmented reality and virtual reality as educational resources

In recent years, the utilization of augmented reality (AR) and virtual reality (VR) has emerged as a transformative approach in education, revolutionizing traditional teaching methods. This study seeks to explore the efficacy of AR and VR as pedagogical resources for enhancing the teaching of the solar system. The research process involved the development of an application comprising two modules, AR and VR, which were evaluated to assess their impact on the teaching process. Furthermore, a comparative study was conducted to evaluate the immersiveness, interactivity, and ease of use offered by these technologies. The findings demonstrate that both AR and VR demonstrate promise in supporting the teaching process, with the VR module garnering particularly positive evaluations. However, it is crucial to acknowledge existing barriers in underprivileged communities, where public schools face limited investments in technology infrastructure. These limitations hinder the widespread implementation of such immersive experiences and their potential to foster new knowledge acquisition.


| INTRODUCTION
The development, incorporation, and application of recent technological innovations have brought about social and economic changes in society, with improvements in telecommunications [8], greater technological development [25], and sustainability [23].These changes, in accelerated expansion, have reached a significant scale and scope, in which several technical studies have suggested that we are beginning a fourth industrial revolution, called "Industry 4.0" [14].Artificial intelligence techniques are being increasingly applied in this context [31], with applications for classification [33], time series forecasting [31] in the energy field [30], security [35], and education [27,43].
Facing the current digitalization process that comes from Industry 4.0 and the constant interference of the excess of available information, education faces the dilemma of being able to dispute the students' attention on several interactive contents.Given the difficulties facing education in the 21st century, the field of teaching has been under transformation to better align with the modern global reality and adopt new pedagogical techniques that acknowledge how individuals fit into contemporary society [7].
Technology is being used increasingly in education [9,20], as the development of new technologies [40] and the use of artificial intelligence [32,34] makes it promising to apply these concepts in the classroom [22].According to da Silva et al. [10], several models can be used, and their choice is difficult since each problem has its particularities.
Based on the need for a school education more aligned with the contemporary world, teaching applications have been using interactive technologies, such as augmented reality (AR) and virtual reality (VR).
According to Cardoso et al. [6], AR and VR differ from traditional media because they provide immersion and interaction in the learning process.VR is characterized by allowing the user to be transported to a reality different from the one in which he is, allowing him to navigate through three-dimensional scenarios.At the same time, AR differs from VR by keeping the user in his reality but adding virtual elements.With the growth of active methodologies, techniques based on AR and VR have become a promising way to encourage educational development in schools [29].
Several studies have been developed in the field of application of games, VR, and AR in the learning process.Ullah et al.'s [38] work presents a discussion on the role of VR, AI, and AR games in teaching science subjects.The authors present the systematic literature review where they report the results of the distribution of studies by country, where it was evident that the vast majority of studies are conducted in developed countries, such as the United States and many European countries, and a very small number of studies are being carried out in developing countries such as Brazil.
In addition, this scenario adds to the challenges and limitations regarding the development of research in public schools, especially in impoverished neighborhoods that face technological restrictions, for example, computer labs, Internet access, or availability of mobile devices.These schools serve an audience that mostly comes from families in a situation of social vulnerability, in the process of social exclusion, mainly due to socioeconomic factors.However, regardless of social class, all children have equal opportunities for quality education.
Considering this scenario, some problem questions are raised: is it possible to use VR and AR technologies in public schools that have access restrictions on access to technological resources?What is the perception of students in these schools when using VR and AR educational applications in class?Can VR and AR technologies contribute to the learning process in this scenario?
This work presents the development of an application in Portuguese to support the teaching of the solar system, a topic covered in middle school geography classes.The application has a module in VR and another in AR, consisting of the same capabilities.From the development of the two modules, an evaluation was carried out with students in the sixth year of middle school to verify the students' experiences in using the proposed application and their contributions to assist in the teachinglearning process.The evaluation tests were carried out at a public school in the countryside city of Passo Fundo, Brazil, which serves the public of low-income families and has a high rate of school dropout.
Thus, this work seeks to carry out a comparative analysis of the use of AR and VR as educational resources to support the teaching of the solar system, content addressed in middle education in the discipline of geography.To this end, students' experiences in using the proposed application and their contributions to aiding in the teaching and learning process of the students.
The paper is structured as follows.Section 2 presents a literature review containing concepts and technologies used in developing the work, as well as related work.Section 3 describes the development of the work.Section 4 presents the results obtained through student evaluation.The final considerations are presented in Section 5.

| LITERATURE REVIEW
This section discusses the main concepts and characteristics of AR and VR, as well as the technologies used to develop the proposed case study.Related works, divided into two groups, are also presented in this section.

| AR
The first reference to the concept of AR dates back to the 1960s when Suther [36] published his doctoral thesis under the name "Sketchpad, a Man-Machine Graphical Communication System."Although, only in the 1980s in the military environment was the first AR project to appear, consisting of an airplane cockpit simulator, mixing virtual elements with the user's physical environment [3].
AR provides the superimposition of digital objects on physical environments in real-time execution using technological devices, enhancing or increasing the user's vision.This requires combining computer vision and computer graphics techniques [13].The user interaction with the virtual elements occurs naturally and safely once the digital content overlaps the user's physical environment.That is, it complements reality instead of replacing it entirely.This process occurs through the camera of the mobile device without necessarily using special equipment.
During the preparation phase of a system, AR software is used to create virtual objects and seamlessly integrate them into the natural environment, complete with certain interactive behaviors Avila-Pesantez et al. [2].SDKs are used to create AR applications, which bring ready-made resources to develop an AR experience.Some examples of software are Vuforia, Wikitude, ARCore, and ARKit, among others.

| VR
The term VR is credited to Jaron Lanier, who coined it in the early 1980s to differentiate traditional computer simulations from simulations involving multiple users in a shared environment [19].There are many definitions of the term VR in the literature.In a simplified way, VR is an advanced interface for computer applications, which allows the user to navigate and interact, in real-time, with a three-dimensional computer-generated environment, using multisensorial devices [16].
For Latta and Oberg [18], VR is an interface that simulates a natural environment that is not easily experienced and allows participants to interact.Specific devices must be used for the user's interaction with the virtual environment.
Therefore, to display the simulated environment, visually coupled displays are a class of systems in which images are displayed directly to the user, who is looking at a device that must follow his head movements.This device usually allows stereo images and sound and contains special sensors that detect the user's head movement and use this information to provide feedback on the displayed image [24].

| Technologies used in the development
This section presents the technologies used to develop the proposed application, demonstrating their characteristics and operation.

| Unity
Unity is a game engine for creating 2D and 3D experiences, developed and maintained by Unity Technologies.Over the years, the platform has matured and now offers tools for creating AR and VR experiences.The game engine is available for Windows, Mac, and Linux operating systems, and the developed applications can be compiled and exported to different types of platforms [39].
The platform allows integration with external libraries through plugins and offers a store of assets, * which can be downloaded and installed.Unity supports the integration of AR and VR libraries, and when integrated, the library's features are added to Unity's functionality [39].

| Vuforia
Vuforia is an AR software development kit that generally uses computer vision algorithms to track various objects, images, or environments in real time.The SDK offers different features to create AR experiences, including image tracking, object tracking, environment tracking, and Vuforia Cloud, among others [41].
For managing the lifecycle of an AR application, Vuforia encompasses tools to create, manipulate, and control AR experiences.Figure 1 presents the main components of the API and their interaction: the Engine, the Observer, the State, the Observations, and the Controller.Each component is described in the following.
• Engine: responsible for managing the life cycle of the AR experience, that is, for creating, destroying, starting, and stopping it; • Observer: responsible for observing a real-world property.In most cases, these are objects known as markers; • State: responsible for collecting information about the scene; • Observation: responsible for collecting information created by the users according to their movement and interaction with the scene.This information is collected by the state; • Controller: responsible for managing the configurations.

| Google cardboard
Google Cardboard is a VR viewer developed by Google to provide immersive experiences to everyone in a simple, fun, and affordable way.To do so, the user can create their viewer using the specifications published by Google or purchase a premade viewer.
In addition, for creating VR experiences using Google Cardboard glasses, Google provides the Cardboard SDK, which provides the essential features for creating VR experiences.These are motion tracking, stereoscopic rendering, and user interaction via the viewer button [15].

| Related works
The related works are divided into two groups: works whose application focus is Brazil in a similar way to this proposal, and works that compare AR and VR technologies in the educational context.
Regarding the first group, some works were found that use AR and VR in the educational context to support the teaching of the solar system, considering applications in Portuguese as a requirement.
In a work developed by Siqueira [28], a web environment was created to visualize the planets of the solar system in AR and VR.Aiming to show the solar system closer to reality, the measurements used in work involve distances between the planets and the Sun, minimum (perihelion) and maximum (aphelion) distance limits, rotations, inclinations, and eccentricities of elliptical orbits.
In the implementation of the work, an HTML page in AR was used with links to the pages developed in VR.On the AR page, students can view the Solar System through several points of view and access the VR pages to manipulate the representations of the planets and orbits with mobile devices, computers, or VR glasses.The authors conclude their work by stating that this is a helpful tool for classroom use because it allows students to visualize and manipulate the graphical representations of the planets, but it is important to note that the tool has not been tested in the classroom.
Another related work is the application to help teach the solar system using AR developed by Matheus Schmitz et al. [21].The application consists of two modules.The solar system module is intended to show the planets orbiting the Sun or Earth, and the solar system Dissection module, where the user can see the planets separately.The development environment used by the authors was similar to the one used in this work for developing the AR module, the Unity platform, and the Vuforia SDK.The application test proposed by the authors occurred with a class of 20 first-year high school students.Students were grouped into 10 pairs to perform the tests, which consisted of profile questions, activities to be performed with the application, and usability questions.The results were positive, especially those related to the motivation to use the tool.Most of the negative comments came from the hardware used to perform the tests, which was a little limited and eventually crashed, generating some frustration in the students.
In 2020 [12], a study was conducted on implementing and using a virtual planetarium.The software was developed to promote the teaching of astronomy in schools in an immersive, interactive, and intuitive way for students.For this, the authors designed and implemented an application that simulates a planetarium using VR, presenting the solar system to the user, respecting the characteristics of proportion, distance from the Sun, rotation, and translation.The interaction with the user occurs through VR glasses and auxiliary control.The user is invited to immerse himself in the solar system, being able to navigate between the planets and obtain information about each of the elements presented in the scene.
For this, the work cited involved the following stages: development, where the modeling and implementation of the software were performed; use of the software by the volunteers; data collection through questionnaires, data tabulation, and analysis of the results.Physical questionnaires were applied to the student users in the data collection stage.The results showed that the developed tool had an excellent evaluation of its usability through the results obtained in the questionnaire.
The case study of the present work shares a proposal very close to the related works.The solution proposed in the work of Siqueira [28] uses the web environment for visualization, while our proposal is an application for mobile devices.In addition, the referred work does not present evaluation tests with the students.The work of Matheus Schmitz et al. [21] focuses on AR, while the work of dos Santos Ritta et al. [12] uses VR, that is, the two technologies (AR and VR) are not included in the same solution.The differential of this work is the comparative study of the use of AR and VR as resources to aid student learning.
With regard to the works of the second group, we have selected three works that focus on a comparative study of AR and VR technologies in the educational context.
Călin et al. [5] aim to bring together the benefits of virtual, augmented, and mixed reality within a classroom, emphasizing their use in the formation of a teacher.The subjects for this study were young students of the Faculty of Automation, Computers and Electronics and fresh graduates of the teacher-training courses.The work brings a series of notes regarding the advantages and disadvantages of technologies and their applicability.The authors highlight that the transformation of classrooms and laboratories in all schools to incorporate VR/AR/MR technologies for the purpose of educating young students and teachers is no longer a bold initiative; rather, it has become a pressing necessity and obligation for the future of education.
Boyles [4] reviews how VR and AR have been used in education, discusses the advantages and disadvantages of using these technologies in the classroom, and describes how VR and AR technologies can be used to enhance teaching at the United States Military Academy.
In a comparison of the two technologies, the author mentions that in some specific areas AR can be a better platform to pursue, in particular because the work in the design of an application is usually less than a similar application with VR.In addition, it is highlighted that AR facilitates users' interaction with the environment, as well as face-to-face interaction with the people around them, and teamwork among students is facilitated with AR, as they can communicate face-to-face.However, implementing this level of communication in a VR environment requires significant overhead, especially if modeling nonverbal communication such as body language and gestures, in many cases requiring the user to hold the device with their hands.The author also points out that these are important aspects that must be considered when choosing the technology that will be adopted according to the scope of the content that is intended to be addressed.
In Anggara et al. [1], the authors suggest using elearning to teach Natural Sciences subjects to third-grade students in Elementary Schools.Their research proposal involves creating lessons that use a virtual approach to showcase real-life events and natural occurrences.The research involves various stages such as analysis, design, implementation, and application testing.
The work presents an implementation which is application-based e-learning using software development through the Unity game engine.This application was only running on the Android platform.The e-learning platform was tested with a small group of five students in 3rd grade and a teacher at an elementary school in Jakarta.The evaluation involved conducting three types of tests: (a) learning e-learning method (teacher does not explain the material); (b) conventional learning methods (without e-learning); and (c) combination learning methods (conventional method and e-learning method).The test results were obtained from the application of pre-and posttest.After testing the effectiveness of e-learning in combination with traditional learning methods, the results showed that students' understanding of the material increased by 24%.Different from our proposal, the evaluation does not compare AR and VR technologies regarding their contribution to learning.
These works bring important aspects regarding the use of AR and VR technologies in the context of education, for example, highlighting the skills that can be developed when technologies are incorporated by the teacher in the teaching process.However, we emphasize that this study differs from the works above in the following aspects: (a) target audience, this study was carried out with middle school students from a peripheral public school; (b) this study developed an application for mobile devices that was used with students to then conduct data collection both regarding the contribution to effective learning and the experience of using technologies.

| AR AND VR APPLICATION
To achieve the proposed objective, an application was designed and developed to assist in teaching content related to the solar system.This section presents details about the purpose of the application, its architecture, capabilities, resources used, as well as aspects of its development.

| Application purpose
Langhi and Nardi [17] seek to answer in their work the following question: why teach astronomy?One of the points raised by the authors is the study of astronomy as a motivating element.In addition, they signal that: Learning astronomy has led the thinking inhabitant of planet Earth to mental restructurings that go beyond intellectualism and knowledge for its own sake because understanding the dimensions of the universe in which we live provides the development of aspects unique to the human mind, such as fascination, wonder, curiosity, contemplation, and motivation.
Astronomy teaching encompasses several fields of study, such as learning about the solar system, a subject presented in middle school.Still, in Langi and Nardi [17], the authors point out the teachers' lack of knowledge of the actual astronomy content and their teaching methodologies.In addition, new teaching approaches have emerged and brought new ways of sharing and acquiring knowledge.
The objective of the case study is teaching the solar system using VR and AR.To do this, the user can view the planets separately and information related to them, such as average distance from the sun; temperature; potential for life; rotation period; translation period; diameter; planet type, and the number of moons.

| Application architecture
A single application was designed with two modules for viewing the planets of the solar system: AR and VR.The application architecture is represented in Figure 2. When the user (student) accesses the application, a page with three options is presented: access to the AR module, access to the VR module and exiting the application.When the AR module is selected, the user needs to use the marker, that is, a printed image that when detected by the application, through the pointed camera, will provide the AR experience.
In the VR module, however, it is necessary to use Google CardBoard with the smartphone attached.The two modules have the same functionalities, the visualization of the planets of the solar system and their information.The AR and VR modules are described in Sections 3.5 and 3.6.
The information for creating the solar system-related content was obtained from the solar system exploration page † from Nasa (National Aeronautics and Space Administration).
The main architecture of the application is composed of several essential layers that work together to provide an immersive and interactive learning experience.Each layer plays a crucial role in the functionality and effectiveness of the application.The following are the key layers of the system architecture.

| Presentation layer
User interface (UI): This layer handles the interaction between the user and the application.It provides a visually appealing and intuitive interface for users to navigate and interact with AR and VR content.It includes elements such as menus, buttons, and interactive 3D models.

| Data management layer
• Database Management: This module handles the storage, retrieval, and management of data related to the application, such as user profiles, progress tracking, educational content metadata, and user-generated content.This ensures efficient data organization and facilitates data retrieval when needed.| 1767 • Security and Privacy: This module focuses on ensuring the security and privacy of user data within the application.This includes measures such as data encryption, access controls, and compliance with data protection regulations.This module is crucial to safeguarding sensitive user information and maintaining user trust.

• Integration with Learning Management Systems (LMS):
This module facilitates the integration of the application with existing Learning Management Systems.It enables seamless data transfer, content synchronization, and interoperability between the application and the LMS.This integration simplifies administrative tasks, such as user management, content deployment, and progress tracking.

| Resources
In

| Application features
To compare the technologies, the AR and VR modules were developed using the same resources and functionalities, respecting the aspects and specificities of each one.The digital content presented in both experiences is the same: a visual representation of the planet in 3D and a panel containing its information.In addition, two arrows are present in both experiences so that the user can scroll through the planets of the solar system.
On the initial screen, the user can access the AR and VR modules and has the option to exit the application.Unity's native resources were used to create the application's interface and to transition between scenes.The initial screen can be seen in Figure 3.

| AR module
The AR experience was created using Vuforia's marker tracking feature, which involves using a marker that works like a barcode.The marker was created using the Figma tool using simple features such as rectangles, images, and text.Figure 4a contains the marker used in the AR experiment.
After the marker is created, it needs to be registered in the Vuforia Database.The image characteristics are extracted when submitting the bookmark, and the tool returns a score between 0 and 5. Images with high scores are tracked correctly, and it is recommended to use bookmarks with a score of at least three points [41].Figure 4b shows the result of the marker evaluation in Figure 4a.The image was evaluated according to the extracted features and resulted in a score of 5 stars.
Then the Vuforia and the database containing the registered marker were imported into the Unity platform.To create the AR experience, the ImageTarget resource was used.This way, the visual representation of the planet in 3D, the panel containing its information, and For the Android operating system, the minimum version 8.0 is required for the correct functioning of Vuforia, while for Cardboard, the minimum version is 7.0.§ Figma: vector graphics editor and prototyping design projects.**https://assetstore.unity.com the arrows to scroll through the planets of the solar system, that is, the digital content is overlaid on the marker.This behavior was possible using the standard Vuforia script methods.
It is necessary to position the smartphone camera in front of the image registered in the database to identify the marker.Once the camera identifies the features extracted from the image, the virtual information is overlaid.In Figure 5, an example of the AR module is shown.

| VR module
To create the VR experience, it was necessary to enable the VR Supported feature in the Unity platform and add Cardboard to the list of supported SDKs.The visualization and projection matrices were automatically adjusted by configuring the aforementioned feature to consider head tracking, positional tracking, and the user's field of view.
After this, the Cardboard SDK was imported into the Unity platform.The SDK offers the use of a crosshair so that the user can interact with the interface.When the user looks at the objects in the virtual environment through the crosshair, a timer is triggered with a visual indicator to inform the user of the state of the interaction.At the end of the timer, the action is executed.It is important to note that Google Cardboard, by default, uses a button consisting of two magnets.When testing the Xiaomi Poco X3 cell phone, the expected behavior was not achieved, and the timer was used for interaction.
In the VR module, a Skyboxes was used to give the impression of a galaxy in the environment, the visual representation of the planet in 3D, the panel containing its information, and the arrows to scroll through the planets of the solar system were added in the scene.The elements were adjusted for comfortable viewing for the users.Figure 6 shows an example of the VR module.The Figure 6 is composed of two images.This creates the illusion of depth because a single image could be seen as something false while using one image for each eye generates the stereoscopic vision.OF RESULTS The evaluation carried out in this study aimed to verify the students' experiences in using the developed application and their contributions to assist in the teachinglearning process.The quantitative and qualitative research methodology was used with a descriptive method and data collection techniques [42].Quantitative research is concerned with numerical representation, with objective measurement and quantification of results, while qualitative research is concerned with the opinion and reality of the subjects involved in the research.
The evaluation stage occurred at the Fredolino Chimango Municipal School, located in Passo Fundo.The school belongs to a neighborhood called Jaboticabal, an impoverished neighborhood that predominantly receives students from families of salaried service providers, who are included in most of the Brazilian population, suffering social pressures of exclusion.
According to Resende and Petterni [26], low educational achievement levels and high probability of dropping out are more often correlated with economic disadvantages, age-grade distortion, teen pregnancy, poorly equipped schools, frustrated teachers, and unobserved factors.It is in this scenario that the evaluation was applied to answer the research questions.
The tests of the AR and VR experiments took place with two 6th-grade classes totaling 24 students who were grouped in pairs to perform the tests.The activity was carried out in the classroom with the supervision of the subjects' teacher and a researcher.Each pair participated in the activities described in Figure 7.
The flow shows that initially the pair of students answered the pretest questionnaire.In the sequence, for each pair of students, one was led to test the AR module and the other the VR module.Then they answered the posttest questionnaire.So that they could evaluate the experience with each of the modules, the students then tested the other module.Finally, they answered the questionnaire regarding the assessment of immersiveness, interactivity, and ease of use.
The Xiaomi Poco X3 smartphone and the Xiaomi Redmi 7A smartphone were used to perform the tests.In the AR experiment, a cardboard-covered marker was provided, and to test the VR module, Google Cardboard glasses were used.The pretest, posttest, and comparison questionnaires were printed and given to the participants.Figure 8 shows the participants testing the application.
The questions in Table 1 were used in the pre-and posttest questionnaires.The objective of the first three stages was to observe the contribution of the use of the application to aid student learning.The process consisted of answering the pretest questionnaire, using a module, and finally, answering the posttest questionnaire.In stage 2, the group that tested the AR module was composed of 12 volunteers, and the percentage of correct answers was 36.67% in the pretest and 48.33% in the posttest.Considering the 12 students who tested the VR module in stage 2, the number of correct answers was 40% in the pretest and 61.67% in the posttest.
Thus, through the results obtained, the students who participated in the tests of the AR module in step 2 had an increase of 11.66% in the number of correct answers, while the VR module had an increase of 21.67% in the number of correct answers.Thus, it can be seen that both technologies can help in the teaching process of students.However, it is noteworthy that the number of correct answers after using the VR module was higher than that of AR.
The purpose of the last two stages was to conduct a comparative study regarding the immersiveness, interactivity, and ease of use provided by the proposed modules.In addition, to obtain an evaluation of the technologies presented.In step 4, the module inverse to the previous one was tested, and after the participant tested both experiences, the questions in Table 2 were answered.
Before the questionnaire was applied to the students, clarifications were made regarding the terms immersiveness, interactivity, and intuitiveness, respectively: the feeling of presence in the environment, the influence on the content, and the ease when using the module besides reintroducing them to the previously used modules.
When analyzing the data obtained through the questionnaire, it can be seen that the VR module was more immersive and interactive than the AR module, while the AR experience was more intuitive than the VR one.As for the evaluation of the modules, 79.17% T A B L E 1 Pre-and posttest questionnaire applied to students, presenting questions with answer options, with the correct option marked.

Questions Answers
What is the translation period of the earth?In addition to applying the questionnaire, during the activity, the researcher observed the students' reactions.It should be noted that the vast majority of children had not experienced the use of AR and VR technologies and their excitement in using them was very evident.Likewise, the teacher's interest in the use of technologies as a support for the learning process and willingness to incorporate them into classes was noticed.
According to Turcanu et al. [37], with the help of AR, teachers have the opportunity to create learning contexts to generate the right framework to stimulate students' curiosity, create a better mood and remove monotony.The authors also mention that given the growing interest of children in state-of-the-art technologies and equipment, such technologies could significantly contribute to increasing the attractiveness of the educational act for children living in rural areas or for other risk categories, to prevent abandonment.and the lack of motivation to go to school.
However, it was difficult to conduct the activity with only two mobile devices, far from an ideal scenario for using these technologies in the classroom.In this scenario, the profile of the students must be considered, not depending on the possibility of them taking their own device.In this way, it becomes evident the need to explore the complexities and restrictions of the incorporation of technologies, particularly in the context of lowincome school communities, urgently lacking the proper investment in technology by the responsible government bodies.Only then, with appropriate institutional and social structures, it will be possible to produce new knowledge and offer unique experiences to students who, otherwise, probably would not have access to these technologies.
The results show that the use of VR and AR in learning activities in this public school makes it possible to bring students and teachers closer to these technologies, generating motivation and improving the effectiveness of the process, in addition to being well accepted in the academic community.

| CONCLUDING REMARKS
This work aimed to develop an application to support the teaching of the solar system based on the use of AR and VR technologies as pedagogical resources.The premise was the development of the application in Portuguese, containing two modules (AR and VR) with the same functionalities to evaluate the contributions in the teaching-learning process of students in the context of a public school in the impoverished neighborhoods.
Considering the data collected in the questionnaires applied to the students, it was possible to verify that the VR module obtained more significant results when compared to the AR module.Regarding the contribution to help in the students' teaching process, when analyzing the answers in the pretest and posttest questionnaires, it can be stated that effective learning occurred when using the application.It is worth mentioning that the number of correct answers was higher after using the VR module.
It was also evidenced that the students considered the VR experience more immersive and interactive, while the AR experience more intuitive.Furthermore, through the questionnaire, the evaluation of the VR module was more positive than the AR module, even though both modules were well evaluated.
In the testing stage, the students are highly involved in the proposed activities.However, there was a greater interest in the VR module due to curiosity when using Google Cardboard.The participants of the research are students from a public school in a community in the impoverished neighborhoods of Passo Fundo, and most of the students experienced for the first time the technologies addressed.‡ ‡ Moreover, other aspects can be considered, such as using the available devices to perform the tests considering that the screen size may interfere with the visualization of the virtual elements.Another aspect that may have interfered with usability was the material used to build the Google Cardboard, which may cause discomfort and the user's interaction with the VR module due to the use of the timer.Finally, relying on a marker in the AR experience may have impacted student immersion.
The limitations of this study are mainly related to the number of devices to perform the tests, which interfered with the number of students who participated in the evaluation of the application.Another limitation was the homogeneity of the sample since the participants were from the same school and were in the same grade level.
According to de Cote et al. [11], AR and VR technologies allow playing, teaching, training, or educating, with the potential to make people empathize with other realities and envision healthier social scenarios.Considering children's interest in state-of-the-art technologies and equipment, the use of technologies such as AR and VR can significantly contribute to increasing the ‡ ‡ Information obtained through an informal report from the teacher and students.attractiveness of the educational act, especially for children who attend schools in more vulnerable areas, to prevent abandonment and lack of motivation to go to school.
However, to achieve these goals, it is essential that there is investment in technology in public schools, which mainly serve students from low-income families.These students are often victims of social exclusion processes and have less access to technology.In addition, for the use of these tools to be really effective, it is also necessary to invest in teacher training.Without proper training, many educators may feel intimidated or unable to use these new technologies in their classrooms.
Thus, as future work, it is proposed to implement new features such as the visualization of the planets orbiting the Sun since the user can only see the planets separately in the current implementation.In the VR module, we intend to improve user interaction through more comfortable VR glasses and evolve the interaction using a control.In the AR experience, it is planned to use the user's location instead of a marker.Finally, a new study will be conducted with a larger and more heterogeneous sample.
With regard to advantages, they are emphasized: (a) a new perspective on the learning process; (b) encouraging practice over theory; (c) developing imagination and creativity; (d) long-term, powerful motivation; (e) Efficient long-distance learning; (f) affordable technology; g) exploiting domains easier.On the other hand, about the disadvantages, it points out: (a) the lack of trained teachers; (b) inexistent digital infrastructure; (c) no funding for digitalization; (d) medical afflictions caused by VR, AR, MR technologies; (e) technology addiction and ignoring other types of teaching.
the development process of the application, the Unity platform version 2018.4.3 was used in conjunction with the following SDKs ‡ : Vuforia version 8.1.10and Cardboard version 1.15.0.The marker used in the AR experiment was created in Figma.§ The 3D models of the planets were acquired from the Unity Asset Store.** It should be noted that the version of the Unity platform used in this work was defined due to the incompatibility of version 2020.3.3 with the Cardboard SDK and version 2019.4.3 with the Vuforia SDK.After some testing, the 2018.4.3 version was chosen.
For correct visualization, it is necessary to use Google Cardboard.† † F I G U R E 4 Marker and features extracted from the original image.(a) Marker and (b) Extracted features.F I G U R E 5 Example augmented reality module.† †

F I G U R E 6
Virtual reality module example.F I G U R E 7 Test step flow.

F I G U R E 8
Participants testing the application.
Result of the students' evaluation after the experience with the use of the modules in terms of immersiveness, interactivity, and ease of use.1771of the students evaluated the VR module as very good, 16.67% as good, and 4.17% as regular, while in the AR module, only 54.17% scored it as very good and 45.83% as good.
Note: The questions and percentages of student responses are presented.DE MORAES ROSSETTO ET AL.|