## 4 Experimental Results
### Subjective Measures
#### 4.3.3 Result and Discussion  
In Table 2, questions 1-12 ask about preferences for the IVR-SDO education system, and question 13 asks about comfortableness for HMD-based learning, and questions 14 to 16 compare preferences between the IVR-SDO education system and Heliviewer. Table 3 summarizes the statistical comparisons between the viewer-based education and IVR-SDO education methods where there were statistically significant differences between the two education methods using Wilcoxon Rank Sum tests. According to the results on the preferences for the IVR-SDO education system, the participants gave a significant preference to the proposed method for all questions except Q4 and Q7. The results demonstrate that the participants felt that they learned in the IVR-SDO education environment better than in the viewer-based education environment. In addition, the IVR-SDO education system provided the necessary tools for learning. Participants also reported that they were so immersed in the IVR-SDO educational environment that they forgot they were experiencing education in a virtual space. In the IVR-SDO educational environment, they could more confidently express their thoughts or ideas than in the viewer-based educational environment. This study indicates that participants felt that they were participating in the IVR-SDO educational environment compared to the viewer-based educational environment. Furthermore, they could easily use the technologies applied to the proposed educational environment and it offered a comfortable educational environment. All participants answered that education in the proposed environment was interesting, and most participants felt that they would receive education if provided in the IVR-SDO educational environment. Most participants agreed that the tool provided in the IVR-SDO educational environment was useful in aiding discussion among participants. Interestingly, all participants felt that learning in the IVR-SDO educational environment was realistic, and that the expert explanations were helpful. Figure 14: Helioiviewer: a solar and heliosphere image visualization tool that enables everyone anywhere to explore the Sun’s variability. Overall, all participants agreed or strongly agreed regarding satisfaction with the environment of IVR-SDO education, as shown in Figure 15. A possible explanation is that the IVR-SDO education system may provide the sense of being in the same place with other participants. This system also could allow participants to encourage their participation to more actively communicate and share ideas. These experimental results have some similarities with those of the teacher-guided educational VR research [26] on VR field trips. Having a networked education VR setup provides some benefits over the standalone approach of having a teacher's recording in the VR space. Most notably, by streaming the teacher's video live, the misunderstandings in communication between the students and the teacher can be resolved on the spot, leading to their reduction and higher gains in test scores. Our research also streams the SDO images live to be immersively visualized in the virtual space, peaking the participants' interest further. Furthermore, similarly to the results from the VR-TBL experiences research, the feasibility of having a remote expert teach multiple participants while experiencing co-presence through an education platform was further verified. However, to answer the question of whether the HMD was sufficiently comfortable that it did not interfere with learning, only a relatively low percentage of participants preferred it because of the weight of the headset. This finding was similarly found in the VR-TBL experiences research and is one of the key issues that must be addressed for long sessions of education in VR.