3D Length Contraction Simulation – Visualizing Special Relativity Free Resource | Grades: 11–14 | Format: Interactive HTML Simulation This free, browser-based 3D simulation helps students visualize the concept of length contraction in Einstein’s special relativity. As velocity increases toward the speed of light, moving objects appear shorter along the direction of motion. Students can adjust the velocity and frame of reference to see this relativistic effect in real time. No software install