Why don’t we fall off the swing?

swing-physics

When my girls go to the park, they love to ride on the swings – especially if there’s a big saucer-swing they can climb on together! They like to be pushed hard and for the swing to go up high. But they want to know why they don’t fall off!?

A swing is a type of ‘pendulum‘, which means it hangs by a wire or string from a fixed point. When it isn’t moving, the swing hangs straight down towards the ground because of a special force called ‘gravity‘. And when my girls sit on the swing, gravity keeps them on the seat.

But, what happens when I push the swing? Well, gravity still pulls the swing and my girls to the ground but, at the same time, the force of my push moves them forwards. So they end up swinging back and forth along an arc-shaped (or curved) path. The combination of gravity and the force of my push working together stops my girls falling off the swing.

It might help to watch this video of pendulums to see how they move. And if you want to learn more about pendulums, check out BBC Bitesize.

Of course, the other thing that stops my girls falling off a swing is holding on to the sides or the ropes. So, as long as they wait for the swing to stop at its downmost point and don’t try to jump off in mid-swing, they will be safe!