the seat of a swing is suspended from chains or ropes. the child sits on the swing and kicks off from the ground with his feet. the swing then starts to swing to and fro. the child can make the swing go higher by pulling (as he goes forwards) and pushing (as he goes backwards) the rope and by making his legs straight as it goes up. once a swing is in motion it continues to oscillate like a pendulum until something brings it to a halt.