This apparatus provides a handson way to verify the law of conservation of momentum using colliding balls of the same size and different masses. Designed for classroom and laboratory use, it helps students connect theoretical concepts with observable results through controlled collisions and measured displacements. Key benefits Demonstrates core physics principles directly: enables experiments to verify conservation of momentum and explore kinetic and potential energy conversion. Improves observation and experimental skills: clear scale lines and a stable rail system support repeatable measurements and data collection. Versatile teaching tool: the set of balls with identical diameter but different masses lets instructors vary mass configurations without changing geometry. Durable and precise construction: aluminum alloy rails and rigid brackets provide a stable track for consistent collision behavior. Main features and specifications Function: Verify conservation of momentum using collisions between equaldiameter balls with different masses. Primary components: aluminum alloy rails, brackets, scale lines, and related hardware for assembly and alignment. Included collision bodies: one metal ball, one glass ball, one plastic ball. All balls have a diameter of 16 mm. Additional mass option: one copper weight included to alter mass distribution or create specific mass combinations. Measurement aids: printed scale lines along the rail allow displacement readings for momentum and energy calculations. Size and compatibility: balls are uniform in diameter to keep collision geometry consistent; system fits typical physics lab tables and demonstration setups. Use scenarios school physics class demonstration: set up a series of collisions to show how momentum is conserved when masses differ while diameter remains constant. Undergraduate laboratory experiment: collect quantitative displacement data using the scale lines to calculate momenta before and after collisions and compare results with theoretical predictions. Science fair or outreach activity: provide a clear, repeatable demonstration that engages observers and supports guided inquiry on momentum and energy transfer. What is included Aluminum alloy rails and mounting brackets with scale lines Metal ball, glass ball, plastic ball, each 16 mm in diameter Copper weight for adjusting total mass Assembly hardware and basic alignment guides Practical notes Use the scale lines and repeatable release points to generate data suitable for classroom analysis and lab reports. Because the balls share the same diameter, mass differences alone drive changes in collision outcomes, simplifying interpretation. The compact, robust rail and bracket assembly supports frequent classroom use and straightforward setup. This apparatus is intended for instructional physics experiments where clear, repeatable verification of momentum conservation and related energy studies is required.