What makes a swing go higher — a big push, or the right timing?
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After you watchWhat makes a swing go higher — a big push, or the right timing?
The short answer
Repeated pushes with a swing’s motion can add energy over many cycles. The resulting height depends on push strength, timing, and losses to friction. A push against motion can slow or reverse the swing, so timing alone does not determine every outcome.
Try this next
- What if none of the smaller taps go with the motion? Set the count to 0 of 14 and predict which peak is higher before replaying.
- How many with-motion taps are enough to change the winner? Try neighboring counts and use the highest-point markers to locate a change.
- Does the last still show the largest angle? Compare each final swing position with its peak percentage.
Now you — bend it
- What if What if you keep the timing perfect but cut every push to a tenth of its strength — does the swing still climb just as high, only slower?On resonance the height keeps growing until the energy you add each swing exactly equals what friction steals — so think about where weaker pushes have to stop, not just how fast they get there.
- What if What if you don't change your pushing rhythm at all, but make the ropes twice as long — does pushing on your old beat still build the swing?A longer pendulum has a slower natural beat (its period grows with the square root of the length), so your old rhythm is now the swing's rhythm only if... predict whether you've gone sharp or flat of it.
- What if What if you set the timing just slightly off — say your pushes come 5% faster than the swing's own beat — instead of way off?A tiny mismatch means each push starts a hair early, so the small phase error piles up push after push; predict how many swings it takes before you've drifted from helping to fighting.
Can you prove it?The highest-point marker can exceed the height of the swing in the final still. — Run a comparison, note each recorded peak, and compare it with the final positions. Friction removes energy between pushes, so a peak records an earlier maximum rather than the ending angle.
Design your own test:Predict whether changing from 0 to 7 to 14 with-motion taps changes the peak by equal amounts.
Explain it to a 6-year-old: A swing has its own back-and-forth beat, and if you give it a little push every time it swings away from you, all your little pushes add up into one huge swing.
The whole story
How it works
Both model swings start identically and follow the same pendulum equation with damping. The left receives 14 stronger impulses against its motion. The right receives 14 smaller impulses, with a chosen number directed with its motion. The default alternates seven against and seven with. Peak markers record the largest angle each reaches; the final snapshot is not the peak.
What people get wrong
Stronger pushes do not automatically produce the higher peak. The mixed pattern in the hidden test must be tried: only half the smaller taps go with the motion, a case not shown in the introductory comparisons.
The catch
With-motion pushes can build energy, but friction removes it between pushes. A smaller push need not reach the same height as a stronger one. The direction and timing of the entire sequence matter.
Questions kids ask
Does pushing harder always make a swing go higher?
No. A stronger push changes the swing’s motion more, but its direction and timing matter too. A push against the motion can slow or reverse the swing. Compare the recorded peaks in the mixed-pattern experiment.
What is resonance?
Resonance is when you push something at the exact rhythm it already likes to move at, so every push adds to the last and the motion grows much bigger than any single push could make it. A swing pushed on its beat is the everyday example.
Why do soldiers break step when crossing a bridge?
Marching feet land in a steady rhythm. If that rhythm matches the bridge's own natural sway, every step adds energy and the bridge can swing dangerously higher and higher — just like a swing. Breaking step makes the pushes land at random moments so they cancel instead of stacking up.
Does a bigger swing take longer to go back and forth?
For a gentle swing, no — the back-and-forth time barely changes whether the swing is big or small, so the rhythm you push to stays about the same. That is exactly why timing the same beat keeps working as the swing grows.
Talk about it
- Guess first: would you rather push a swing hard once, or give it ten little taps? Why?
- Where else in the world do you think timing matters more than how strong you are?
- How do you think your body knows when to push a swing without counting?
For grown-ups
The lab uses the same damped pendulum equation for both swings and the same fixed physics steps in animated and calm tellings. A deterministic schedule spreads 0–14 with-motion impulses among 14 pushes. This is an impulse-direction model, not a continuous sinusoidal frequency sweep. Small-angle pendulum periods depend mainly on length and gravity; large-angle periods also depend on amplitude.
Keep going
What else makes you wonder?
- What gives a swing its own beat in the first place — the ropes, the seat, or the kid?
- Are there other things hiding their own secret rhythm, just waiting for the right push?
- If timing can build a swing huge, could the wrong timing be used on purpose to stop something?
More to explore
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