## 2 Materials and Methods
### Product of Comparative Experiments  
#### 2.2.1 Division of Comparison Groups  
According to the teaching status quo and goals, the aim of this experiment was to explore the memory effects and cognitive load of VR teaching versus traditional teaching at the South China University of Technology (SCUT). SCUT is a representative engineering higher-education institution in China, comprising a significant proportion of civil engineering students in southern China. Each year, a total of around 105 junior students in at the university were required to take the construction course. It is understood that none of these students have had access to or used VR devices before, nor have they been involved in practical training or visits related to coiled waterproof roofing and therefore will not be affected by the relevant experience in assessing learning outcomes. To improve the efficiency of the experiment, the participants were randomly selected using a random sample of 50 out of 105 students. The 50 selected participants were then divided randomly and equally into two groups: VR teaching as the experimental group and traditional teaching as the control group. Before the start of the experiment, the participants were given a brief ten-minute intensive training session by the developer of the program to ensure that each student had the same level of understanding of the basic operation of the VR devices.  
With students wearing VR headsets, guided by text and sound prompts, and holding the controllers in their hands to move and manipulate tools, the VR teaching is carried out, and the following three teaching tasks are completed: learning how to treat the base and apply the base agent, learning the requirements for treating special areas and knowing the hot-melt process. In order to provide a better understanding of our VR model, we have provided the VR program public download site for readers' reference [29].  
Traditional teaching in China can be introduced in three stages: before the class, students read the textbook to preview the knowledge they will learn; during class, the teacher uses multimedia, such as slides and videos, to explain the knowledge to students, who refer to the textbook, receive lectures from the teacher, and mark key points of knowledge; after class, students complete their homework and take the initiative to ask the teacher for advice if they have doubts. Specifically, the civil engineering construction course is highly practical, covering a wide range of construction techniques, technologies, machinery and other related content. The textbook usually uses textual descriptions combined with pictures and diagrams to show the content, while the teacher adds pictures and videos from the construction site in addition to the textbook to give students a more realistic and concrete explanation of the course content. Although the main topic of the course is various construction techniques, the course is still basically taught with textbook. Traditional teaching allows for real-time interaction between teachers and students, with students' questions being answered quickly by the teacher and being able to refer back to the textbook at any time, but the process lacks student's immersive experiences of construction practice.