## 3 AR Geography Applications
### AR App for 6 th grade: Earth as a Celestial Body  
The third AR app also refers to the pupils of the sixth grade, but it focuses more on teaching them the Earth. When the pupil opens the app, the main menu appears, which includes some general instructions on how to play the game (Figure 20). Below the instructions, there are seven buttons, each of which is a different game that corresponds to a specific chapter of the school textbook, according to the Greek curriculum. The first game is called the \"Orbit and rotation of the Earth\" (Figure 20). When the pupil selects this game, the camera is activated, and s/he has to scan the target image that exists in the corresponding chapter of the textbook. Then, the augmented 3D objects, which are the Earth and Sun, are placed over the textbook. Firstly, a 3D animation of the Earth's orbit around the Sun is shown, and afterward, a relevant question is displayed that the  
Figure 19: The mini game “Travel” of the game “Continents”. Figure 20: The main menu (**left**) and the game “Orbit and rotation of the Earth” (**right**). pupil has to answer by selecting one of the three buttons that are below the question. After choosing one, the pupil moves on to the next activity. Similarly, a 3D animation where the Earth rotates around itself appears and then the pupil selects one of the three answers (buttons) to answer the question. If the answer is either correct or not, appropriate audio and visual feedback is given to the pupil. The main buttons that are on the bottom of the screen during the whole game are a reset button, which restarts the game, and a menu button that leads to the main menu. The second game refers to the \"Poles, equator, parallel circles, and meridians of the Earth\" (Figure 21). The camera turns on and the pupil scans the corresponding image from the textbook. The 3D model of the Earth appears, and the pupil is ready to play the game. The aim is to answer the questions one by one by selecting one of the three buttons that appear below each question. For example, one question could be what the horizontal or the vertical red ring around the Earth represents. The pupil selects each time one of the three answers and moves on to the next one. Similar to the first game, audio and visual feedback is provided to the pupil. The third game contains material from the book chapter \"Earth's Axis and Rotation--Day and Night\" (Figure 22). The pupil selects this game from the main menu and scans the corresponding image. The 3D model of the Earth appears on the screen. Additionally, a Greek flag is placed where Greece is located, and the Sun illuminates the Earth. The purpose of the game is to rotate the Earth so that night becomes day in Greece. Once the Earth is rotated correctly, the game is over, and the rotation feature is disabled. Then, a tick appears on the screen, followed by fireworks and a sound indicating to the pupil that the game is over. Additionally, there is an info button that consists of the game instructions and some relative information. Figure 21: The game “Poles, equator, parallel circles, and meridians of the Earth”. The next game is about \"Our Solar System\" (Figure 23). The game is selected by the pupil and after scanning the image from the textbook the game starts. Firstly, a 3D representation of our system appears, including the Sun in the center and all the planets in a row on the right. There are also some concentric circles (rings) which represent the distance of each planet from the Sun. Each circle has an available position in which the pupil must place the correct planet. Additionally, there is a dropdown list located at the top left of the screen, where the pupil can select the planet for which s/he wants to learn more, and the relative information appears at the bottom. As long as all the planets are at the correct distance from the Sun, the game is completed, and feedback is given to the pupil. The fifth game refers to the \"Atmosphere\" (Figure 24).