Using an air jet to make a ball appear to levitate is an old physics lab trick; the air rushing around the ball traps it in a low-pressure pocket. But guiding "floating" balls through an obstacle course of hoops, making asymmetrical objects like apples and water bottles float as carefree as perfect spheres, or launching balls across a room with precision accuracy? That's impressive.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.