We present our work in progress on the development of a web-based system for music performance with virtual instruments in a virtual 3D environment, which provides three means of interaction (i.e physical, gestural and mixed), using tracking data from a Leap Motion sensor. Moreover, our system is integrated as a creative tool within the context of a STEAM education platform that promotes science learning through musical activities. The presented system models string and percussion instruments, with realistic sonic feedback based on Modalys, a physical model-based sound synthesis engine. Our proposal meets the performance requirements of real-time interactive systems and is implemented strictly with web technologies.