Development of the MARPEX App Embedding the Mobile Augmented Reality Factors for Learning Motivation in Science Experiments

Mobile Augmented Reality (MAR) has grown exponentially over the last four decades from imagination to real physical experience, especially in education. Previously, experts have completed the concepts of effectiveness, usability, acceptance and understanding in designing MAR applications to introduce and expose technological advances. However, most of these applications are addressed extensively for classroom science learning, while science experiments receive little attention. Students have to go through difficulties in understanding the phenomena of science and consequently become dissatisfied with their grasp on basic knowledge and eventually cannot pursue higher education or career related to science. This paper presents the development of Mobile Augmented Reality for Physics (MARPEX) application for high school students. The purpose of this application is to enhance the learning motivation in science experiments through the content of modern science. It aims to provide an individual learning experience for each student in science experiments. The MARPEX app design has gone through several phases of filtering and evaluation based on the specified objectives. This application needs to maintain the factors necessary to achieve this goal. This app has been designed and developed specifically for science (physics) experiments on the topic of electromagnetism. The application encrypts several experimental instances with the addition of good visualization to understand this phenomenon and has real-life experimental experience.


Introduction
Lack of student enrollment in science is a global issue that needs immediate attention. Lack of experience significantly affects students' confidence to pursue a field. This is indicated through the enrollment of students in science or STEM based learning. The actual hands-on learning experience is important in science-related subject matters, as science is related to many phenomena that do not exist in the real world. Good visualization skills are required to understand and bring to life experiences within their respective environments. Thus, there is a growing interest among MAR experts to enhance the learning experience, engagement, effectiveness, acceptance of MAR use in science education. Content analysis identifies more than 20 previous studies between 2008-2019 on the application of MAR in science learning [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [49], and [50]. Though, there are studies indicated that AR in science is capable as a teaching tool which suits a classroom learning [23], [23], [24], [25], [26] and [27]. Among these studies, students' motivation problems are not realized. This is because students' motivation is an important concept in learning [51], [52]. After all, students' motivation increases their attention, confidence and satisfaction in science learning. Unfortunately, students have significant visualization constraints in science learning due to their inexperience [6] and [28]. Similarly, little is known about how to increase students' motivation in science experiments. Therefore, this paper discusses the design and development of the MARPEX app for students' motivation through MAR and also for validating the Mobile AR in science experiment on learning motivation (MARSELM) conceptual model.

Technical Requirements
The MARPEX app runs on Android smartphones or tablets with the addition of Graphical User Interfaces (GUI). GUI is a proven method for interacting with applications using items such as buttons, icons, and menus used by most modern operating systems (OS). The MARPEX app is developed with features such as navigation buttons, information buttons, and help buttons to enhance interactivity and the effects of experimental learning. The MARPEX app uses the smartphone screen to view the virtual objects.
Technical requirements are essential to meet the hardware to make the application fully functional and the user-friendly MARPEX app. The MARPEX app runs on the minimum operating system (OS) of Android 4.1 (Jelly Bean) and also includes a set of application programming interfaces (APIs). Next, the MARPEX app test conducted using the Samsung Note 5 Android device with Android OS.1 specification, 32GB of storage, 1.5 GHz processor, 1440 x 2560-pixel resolution and 16-megapixel rear camera and works smoothly. The presence of a rear camera is essential in mobile devices for detecting AR markers.
These markers are usually rectangles of images that have been printed on a piece of paper and placed on the scene to identify the place where digital information is presented. Tracking methods involve registering what the camera captures and linking it to an image that a 3D computer produces. The interaction flow begins with the AR marker (on any stable surface), where the smartphone camera scans the image to reveal the encrypted material. The MARPEX app requires a solid surface image to act as a marker and is measured by the preferred font type, size and width and height. Then, scan the customized AR marker through the android device. As a result, the application displays 3D overlapping computer materials on the screen. The marker's sizes (width and height) were set during development. The size of the markers and the types of fonts used during customize the marker is essential, as the camera only displays encrypted 3D objects when recognizing the same size scale and target font type. For instance, if the target marker is twenty units in width and the camera moves from the left edge to the right edge of the marker, the image will remain at twenty units along the x and y axes [29] and [30]. The display layout describes the process involved in running MARPEX app including users, android devices and target markers. To start the app, users must start the application from the smartphone through a perspective view. To enable the application, users need to scan the printed AR markers. Once the marker, scanned and recognized by the device camera, 3D objects are tracked and displayed on the screen. Users can see a 360 o view of the added object as the user moves the smartphone camera within the marker area (as long as the device camera can detect the unique design of the AR maker). Further information on the use of AR markers will be discussed when discussing the development of the MARPEX app.

MARPEX App Architecture
This paper introduces the MARPEX app, where by the MARSELM conceptual model has been embedded in its development. The initial discussion on content making and initial design and development of the MARPEX app discusses our previous work [31]. This paper discusses in detail on technical requirements during the development of the MARPEX app. A two-dimensional (2D) architecture first designed for the MAR environment employed to develop the app. A 2D sketch on A4 paper intended to guide users in the development phases to illustrate how the interface and functions were executed. Thus, the 2D sketch is used in this study to design the MAR app architecture. The architecture consists of several components that include; content making (text, audio and animated 3D model), development tools, AR markers and scenes to complete the assembly procedure, as shown in Figure 1.
The architecture of the MARPEX app shows that the app design passes through different stages through the use of several tools. The utilization of the MARPEX app requires the interaction of the device's camera with the AR markers, as depicted in the development tools section. The MARPEX app architecture requires a new database created from the Vuforia, an AR online database [32], to set a target marker for each experiment. Single target images are selected with customized widths and dimensions for the MARPEX app. The image needs to be uploaded to be the target of the database. It enables the activation of the author section in the Unity 3D software [33]. Simulation objects are displayed on the mobile screen for users to interact with the MAR app. Java Software Development Kit (JDK) and Android Software Development Kit (SDK) are the software development tools to build the MARPEX app for Android phones and tablets. The JDK describes the objects or scenes used in the development phase and also store the enhanced content in the storage of the database. It also publishes the apk file for Android phones and tablets, which can be used to launch the MARPEX app.

App Development
The MARPEX app was designed specifically for enhancing students' motivation in a science experiment. The development phase involved with content making and integration of the MAR app on the android device. More than one software utilized in the development of the MARPEX app includes; science apparatus modeling (Blender), Android app development SDK (Vuforia SDK), and integration of MARPEX app into the android device (Unity3D version 2014).

Contents of the MARPEX app
The first stage in the development phase is content creation. It began with gathering information regarding the experiments and discussion with a content expert (science teachers).The content of the MARPEX app consists of an animated 3D model for the experiment section and text and audio effect for the quiz section. The key reason for allowing animated 3D models to be compatible with the three experiments is to suggest MAR in a science experiment. The ultimate purpose is to assist students' visualization of science phenomena and hands-on live experience doing experiments. Thus, it is vital to employ suitable media to convey the content to highlight visual senses due to the limitation in visualizing the science phenomenon. The contents of the MARPEX app tackle the experiment syllabus from the electromagnetism topic. The MARPEX app is a student-oriented learning tool; hence, the proposed content has been verified and accepted by experts at every point of development. The experts involved are classified as content expert (Science Teacher) to review the content and design; and functionality experts (lecturer from relevant background) to test the suitability of the process of interaction of the MARPEX app.
The MARPEX app can only function with an AR marker. Figure 2 illustrates the AR marker used to access the virtual apparatus. Once the marker recognized, the MARPEX app displays the overlapping virtual apparatus (animated 3D model) on the mobile device screen. Photoshop software was used to customize the AR marker. A device database was created using the online database of Vuforia, and a new target was identified, and a unique name was given. For the MARPEX app, the targets include an animated 3D model for the experimental section, while text and audio included in the quiz section. The target sets the dimension or size, and then the target image file is uploaded to the Vuforia database. The compatible AR marker saved as a JPEG or PNG image file format using Vuforia. The Blender was used for modeling the 3D apparatus and for incorporating animation. Unity3D software has been used to integrate the animated 3D content of the MARPEX app with the augmented reality SDK.

Incorporation of MARPEX app on android device
Vuforia SDK package imports into the development platform to create the augmented reality surface. Several features were determined for the MARPEX app, as discussed in the architecture of the MARPEX app. These features comprised of image targets, text targets, audio targets, animated 3D model targets, and the SDK project file for android development. The AR project marker file was downloaded from the Vuforia database after the custom image was uploaded as a target marker. A Unity Editor file was selected to match the authoring development of the Unity3D software. Subsequently, the unity editor format was set up with Vuforia SDK package, downloaded and import in Unity 3D for further development. The development of the MARPEX app requires the merging of Vuforia and Unity3D software. The C++ JavaScript used for further development of the application. The development of the MARPEX app that consists of 3D content making, animated the content, interaction and incorporation to the android device, test the functionality of Unity3D.
The main interface of the MARPEX app includes four main buttons consisting of three sets of experiments and a quiz. Further, two icons include; icon for navigation guide button for first time user as "i"(on the left side-bottom) and icon for the exit button as "x" (on the right side-top) were also included as shown in Figure 3. The designs of the icons designed and import in the Unity workspace. A transparent background was set in the Unity workspace, serving as the MARPEX app's background. Since the app requires a scene switch, an object named Manager created, and the script written in C++ JavaScript for the corresponding icon was attached to the object. Therefore, when an AR marker is scanned, the virtual apparatus that is attached to the AR marker appears on the android devices' screen.
MARPEX app intends to enhance students' motivation in science experiments through the use of the MAR platform. The MAR app is a tool that helps the students to improve the visualization and experiment skills in predicting the phenomenon that takes place and the possible outcome. All the MAR factors of the MARSELM conceptual model were encrypted in the design and development of the MARPEX app. The app comprises of virtual apparatus in the form of an animated 3D model, which were implied into the AR markers so that the students can view the enhanced contents when positioning the AR marker in front of their android device. Figure 3 shows the wireframe for the primary interfaces of the MARPEX app. The interfaces and steps in operating the experiment's animated 3D apparatus for each experiment have also been highlighted. Each experiment consists of several hypotheses where students can manipulate the manipulative variables to test their hypothesis for the respective experiment. In the meantime, the MARPEX app provides the user with enhanced visualization experience with instant virtual experiment experience. Conversely, it is essential to show the relationships between the MAR factors of the conceptual model and the developed app. The following section provides some grasps about the MAR factors of the MARSELM conceptual model that have been embedded into the app.

Enjoyment
Enjoyment is the state or process of the fun of something and the act of owning and benefiting from it. Enjoyment is defined as the emotion of excitement about the experience [34]. The enjoyment factor is crucial in the development of the MARPEX app as students quickly lose concentration and get bored. It is essential to add something enjoyable and cheerful to improve the enthusiasm of students in a science experiment. Enjoyment is always seen as the result of the fulfillment or fulfillment of one's desires, but some researchers have stated that pleasure goes beyond enjoyment, commitment, satisfaction and emotional fulfillment due to physical movement and activity [35], [36], and [37]. The emotional excitement using MAR has addressed in previous studies so far [4] and [38], and the enjoyment of physical movement has been largely unnoticed. Moreover, enjoyment is a good feeling that can reduce tension and increase learning motivation [39]. Hence, the MARPEX app drives the enjoyment factor with some great features like instant and manipulative variables, pan and rotation 3D tools, and monitoring controls while observing the flow of 3D animation tools while scanning the AR markers.

Realism
Realism is the quality or the fact that a person or thing is represented in the right way of life. Realism can be categorized as the proper appearance and function of reallife equipment [40]. Meanwhile, using rendering methods such as Photo mapping, additional objects can be created to have a realistic look. Previously, there was a lack of reviews that considered the importance of realism in the appearance and functionality of motivational learning. [41] pointed out that "models are the recommended medium when realism is essential to learning." The more 3D tools in the real world, the more students can connect to the experiment internally. Therefore, the realistic factor included in the development of the MARPEX app was in terms of color and size of 3D apparatus, dynamism, sound effects, and 360 o viewpoints.

Usability
Usability, or can be considered as "ease of use" and "usability" focuses on evaluating interactive systems [42] and [43]. ISO defines usability as "the extent to which a product can be used by a particular user to achieve a specific goal with effectiveness, efficiency, and satisfaction in the context of specific use. "Usability" refers to methods for improving ease of use during the design process. Usability is embedded in the design of the interaction study, where interactions between users and applications occur. This study outlines that interactions between users and applications should be user-friendly and useful. Unnecessary interactions can lead to a negative impression. The usability factor is encrypted in terms of usefulness and ease of use where students can easily share applications, the app can operate in offline mode, and can re-do the experiments indefinitely. The transition from one 3D tool to another is done quickly on the same screen. The unnecessary transition screen and onscreen information are avoided in order to give students the space to build their own learning experiences. The above discussion pertains to three key factors (enjoyment, realism and usability) of the MARSELM conceptual model introduced as of the MARPEX app after the development phase. [44] stated that an average human being acquired knowledge through visual senses (75 percent), hearing senses (13 percent) and other senses (12 percent). Thus, learning would be more productive and long-lasting if learning could trigger the senses, such as hearing, sight, touch [45] and [46]. The interplay of various features such as 3D modeling, animation, graphics and audio display in a technology-integrated learning environment is essential. The use of threedimensional (3D) models is vital because it provides an opportunity to visualize and experience learning from a variety of perspectives. 3D models may engage students, but static 3D models may not engage students continuously [22], [47] and [48]. Therefore, animation 3D models designed to attract attention and help to overcome the visualization problem. It also shows the ability of the MAR application in a science experiment to enhance student motivation.

Conclusion and Future Work
This paper has discussed and elaborated on the development of the MARPEX app in a science experiment to enhance students' motivation. The discussions on the technical requirements, the MARPEX app architecture, and the MARPEX app development continue to focus on the virtual content of the MARPEX app and the incorporation of MARPEX on an android device. Besides, there is a discussion on the three main MAR factors of the MARSELM conceptual model in the MARPEX app. Future work includes the evaluation of app users and experts. This paper is expected to guide future developments in the MAR app in a science experiment to enhance student motivation.

Acknowledgement
Our deepest gratitude goes to the Ministry of Education for supporting us by funding the Fundamental Research Grant Scheme (FRGS), and our utmost gratitude also goes to Universiti Utara Malaysia for other supports and facilities provided that have facilitated the research process along this year.