“This working particle accelerator uses a simple system of spinning wheels to accelerate a LEGO ball around a ring. Although the propulsion system is different than that of a real particle accelerator, it’s a great way to illustrate the concept. Not to mention, it is fun to play with. Multiple balls can be inserted simultaneously and obstacles can be introduced for the ball(s) to collide with.”
You can read more about this potential LEGO Ideas set here.