simpler explanation? when you hold the slinky in the air by the top, the weight of the bottom is equal to the force of the tension of the spring, otherwise the

simpler explanation? when you hold the slinky in the air by the top, the weight of the bottom is equal to the force of the tension of the spring, otherwise the bottom wouldn't remain stationary. once you let go, the force from the spring should decrease as the top falls downward. But the top gathers up more of the bottom as it falls, so the smaller bottom needs less force to hold it in place. Apparently the decrease in mass of the bottom and decrease in tension of the spring exactly cancel each other out.