What sends a swing way up high — pushing a lot, or pushing at the right time?
A swing has its own little beat… back and forth, back and forth, tick-tock. Now two kids each give their swing the very same gentle pushes. One kid pushes in time with the beat, every time it swings away. The other kid just pushes any old time. Both swings start down low and still. Ready to guess… which swing flies way up high — the one pushed in time, or the one pushed any time?
After you watchWhat sends a swing way up high — pushing a lot, or pushing at the right time?
The short answer
A swing flies high when the little pushes land in time with its own back-and-forth beat, not just because you push a lot. Each on-the-beat push adds to the one before, so tiny pushes stack up into a giant swing. Pushing at any old moment barely helps, because the off-beat pushes get in the swing's way.
Try this next
- What if you push but at the wrong moment on purpose? Wait until the swing is coming back toward you, then push — and guess first whether it climbs higher or slows down.
- What if the pushes are super tiny but always in time? Give the smallest taps you can, but each one right on the beat, and predict whether the swing still climbs high or gives up.
The whole story
How it works
Every swing has its own steady rhythm — back and forth, the same beat each time. If you give it a little push each time it starts swinging away from you, every push pushes the same way the swing is already going, so the pushes add up and the swing grows higher and higher. Push at the wrong moment and you bump into the swing as it comes back, slowing it down, so it stays low. It's the timing of the pushes, not how many or how hard.
What people get wrong
Little kids often think you just have to push a lot, or push hard, to make a swing go high. But two swings given the exact same gentle pushes end up totally different: the one pushed in time with its beat soars, while the one pushed any old time barely moves. When you push matters more than how much.
The catch
Pushing in time turns tiny taps into a huge swing — but you have to wait and push each time it swings away, matching the beat. Pushing any old time feels easier and faster, but the pushes fight the swing and it stays low. A gentle push at the right moment beats lots of pushes at the wrong moment.
Questions kids ask
Why does pushing in time make the swing go so high?
Because each push goes the same way the swing is already moving, so it adds to the push before. Push, push, push, all in time — and the little pushes stack up into one big swing.
Why doesn't pushing a lot work?
If the pushes land at the wrong moment, some push the swing forward and some bump it as it comes back, so they cancel out. Lots of pushes at random times barely move the swing. Timing wins.
When is the right time to push a swing?
Push gently each time the swing starts moving away from you, at the bottom of its path. That's when your push goes with the swing and helps it grow.
Talk about it
- Guess first: would you rather push a swing lots of times any old way, or just a few times at the right moment? Why?
- Can you clap a beat that matches how the swing goes back and forth?
- Where else do you think doing something at the right time matters more than doing it a lot?
For grown-ups
A playground swing is a pendulum with a natural frequency set by the rope length, not by the size of the push. Push it in phase with that rhythm — a little force added each cycle, always in the direction of motion — and the energy accumulates so the amplitude grows far beyond any single push. That stacking-up effect is resonance. Push off-rhythm and the force drifts in and out of phase, alternately adding and removing energy, so the swing stays small. The same physics rings a wine glass at its pitch and is why marching soldiers break step crossing a footbridge.
Keep going
What else makes you wonder?
- What gives a swing its very own beat — the ropes, the seat, or you?
- Can you make a swing go high all by yourself, just by kicking your legs in time?
- What else around you has its own secret beat, waiting for a push at the right moment?