Virtual Reality-based Virtual Lab Product Development in Developing Students' Spatial Abilities Using the Van Hiele Theory Approach

In learning during the current pandemic, there are many problems, one of which students cannot meet face to face on campus, one of the learning problems that often occurs is learning geometry in universities, geometry is a scourge lesson before the pandemic both at Universitas PGRI Semarang and other private universities so far, students are required to use a compass and ruler in making flat shapes and building spaces so they have to face to face with the lecturer, but now it can't because it is still online, therefore it is necessary to make learning media that aims to help students sketch flat shapes and build spaces virtually with practice making it online with a van hiele theory approach, so that the resulting product is truly capable of elaborating between technology, the right learning approach and the content of lecture materials on an ongoing basis, then a virtual media lab for geometry courses is created that is able to display material virtually and practice making material designs virtually with the van hiele theory approach, the research method used using the ADDIE R & D model ( Analysis, Design, Develop, Implementation and Evaluation), the result of this study is a virtual geometry lab application with van Hiele theory that is valid according to material and media experts with an average score of 93 and 95 can be used as an online geometry learning media solution. at Universitas PGRI Semarang, for student responses below 40% very agree, 59% agree and 1% disagree using virtual lab geometry it is was able to improve students' spatial abilities, Results The effectiveness of the media after being tested in the experimental class obtained an N-gain value of 0.39 which was better than the control class which only obtained an N-gain value of 0.02, then a virtual media lab for geometry courses is created that is able to display material virtually and practice making material designs virtually with a van hiele theory approach.The five steps in van Hile's theory have been well implemented consisting of (1) Visualization level, (2) Analysis level, (3) Abstraction level, (4) Formal deduction level, (5) Rigor level.