Abstract: eXtended Reality (XR), which includes a variety of augmented, mixed, and virtual reality (AR/MR/VR) environments, are becoming more common in both K-12 schools and industry as a means of providing interactive learning experiences. This poster session will share several prototypes have been developed using the web-responsive ThreeJS library to explore design consideration for future XR models and simulations. These web-based prototypes are designed to run across a wide variety of devices such as laptops, tablets, smartphones, and VR headsets without the installation of additional software. This session will share the lessons learned the from development of three web-responsive XR prototypes and provide design considerations for future research projects about levels of immersion.