This slow-motion video of a man dropping a Slinky from a ladder has got us at The Freaky stunned.
The clip shows the multi-coloured toy spring “suspended” in the air. Seemingly defying the law of gravity. But, on closer inspection and after speaking to smarter people than us, it actually shows physics at work.
The spring is pulling up, while gravity is pushing down. Thus, they are in equilibrium and “suspended” in the air until the weight plus gravity pushes the whole thing down.
Gravity is pulling the entire system down but the upper part (which is falling down) is pulling the lower part upwards hence the lower part is stationary and the upper part is falling. Only when the top meets the bottom does the change in force make the whole slinky move downwards.
Or put in another way, the tension/potential energy in the coil keeps the bottom of the coil from going down, the bottom acts like a stationary object suspended from a wire, but as the coil comes down the potential energy is converted to kinetic energy.