Chaos to Harmony: The Secret Behind 15 Pendulums Dancing in Perfect Sync

I’m Ken Kuwako, the Science Trainer. Every day is an experiment.

Fifteen pendulums sway, ripple like waves, twist into mesmerizing patterns, and then somehow return to their original positions as if nothing happened. The moment I saw this exhibit at the Science Museum, I couldn’t help but stop and watch. Take a look at the video below.

Discovering the 15-Pendulum Display

I came across this fascinating 15-pendulum exhibit at the Science Museum. Just when it seems the pendulums have fallen completely out of sync, they suddenly begin performing an ever-changing dance of patterns.

Why Is It So Beautiful?

At first glance, the setup is surprisingly simple: fifteen pendulums, each with a slightly different length. Yet hidden within that simplicity is a breathtaking display of physics in action.

A pendulum’s period—the time it takes to complete one full swing back and forth—depends on its length. This property is known as isochronism. Longer pendulums swing more slowly, while shorter ones swing faster. It’s a basic principle, but when fifteen pendulums of different lengths move together, they create intricate and elegant patterns that look as though they were carefully choreographed by a master dancer.

Why Does Everything Reset After Two Minutes?

The entire system returns to its starting arrangement after about two minutes. This isn’t a coincidence.

Each pendulum has been carefully designed so that, over a two-minute interval, it completes a precise whole number of oscillations and arrives back at its starting position. For example, if the longest pendulum completes 51 full swings in two minutes, the next completes 52, the next 53, and so on. The lengths are calculated to make this happen.

Although every pendulum follows its own rhythm, they all reunite perfectly at the starting point exactly two minutes later. This phenomenon can be related to concepts such as beats and the periodic re-alignment of oscillating systems.

Imagine fifteen musicians playing at slightly different tempos. For a while, their rhythms drift apart and create complex combinations. Then, at one magical moment, every performer strikes the first beat of the measure together again. That’s exactly what happens here after two minutes.

What Kinds of Patterns Appear?

During those two minutes, the 15-pendulum system constantly transforms.

At one moment, all the pendulums seem to move together. A few seconds later, they form sweeping waves. Then they appear to twist into spirals, split into groups, or create entirely new shapes.

No pattern ever repeats during the cycle.

This happens because the phase—the timing difference between each pendulum—is continuously changing. In physics terms, what you’re seeing is a visual masterpiece created by phase interference.

Be sure to watch until the end. You’ll experience a form of moving art that rarely appears in science textbooks, yet perfectly showcases the hidden beauty of physics.

Contact & Information

Bringing the wonder of science closer to everyday life! Here you’ll find fun science experiments you can try at home, along with easy-to-understand explanations and helpful tips. Feel free to explore the site and discover something new.

・The content from Science Notebook has been published as a book. Learn more here.
・Learn more about Ken Kuwako here.
・For writing, lectures, science workshops, TV consulting, appearances, and other inquiries, click here.
・Follow updates on new articles on X!

Science Notebook Channel features exciting experiment videos!

６月のイチオシ実験！

レモンやオレンジで風船を割ろう！インパクトが抜群のリモネン風船の実験

テレビ番組監修・イベント等のお知らせ

• 6月26日（金）　公開研究会「脱作業化！デジタル化と段階的指導で実現する オームの法則の探究」
• ６月28日（日）　ダビンチマスターズ＠昭和女子
• 6月30日（火）　6/30　23:56〜　【科学監修・出演】「地球まるごと大実験ネイチャーティーチャー」（TBS）
• 7月18日（土）　教員向け実験講習会「ナリカカサイエンスアカデミー」の講師をします。お会いしましょう。
• 12月26日（土）　ナリカサイエンスアカデミー（教員向け実験講習会）開催

書籍のお知らせ

• ７月16日発売　『高校入試 分解問題集 理科』（学研）…難しい問題も小さな問題に分解することで、問題を解くことができます。そんな分解の技術が身につくように深く関わりを持って作りました。
• 『大人のための高校物理復習帳』（講談社）…一般向けに日常の物理について公式を元に紐解きました。特設サイトでは実験を多数紹介しています。※増刷がかかり６刷となりました（2026/02/01）
• 『きめる!共通テスト 物理基礎 改訂版』（学研）…　高校物理の参考書です。イラストを多くしてイメージが持てるように描きました。授業についていけない、物理が苦手、そんな生徒におすすめです。特設サイトはこちら。

各種SNS（更新情報をお届け！）

【日本語】X(Twitter)／instagram／Facebook　【英語】BlueSky／Threads

Explore

• 楽しい実験…お子さんと一緒に夢中になれるイチオシの科学実験を多数紹介しています。また、高校物理の理解を深めるための動画教材も用意しました。
• 理科の教材… 理科教師をバックアップ！授業の質を高め、準備を効率化するための選りすぐりの教材を紹介しています。
• Youtube…科学実験等の動画を配信しています。
• 科学ラジオ …科学トピックをほぼ毎日配信中！AI技術を駆使して作成した「耳で楽しむ科学」をお届けします。
• 講演 …全国各地で実験講習会・サイエンスショー等を行っています。
• About …「科学のネタ帳」のコンセプトや、運営者である桑子研のプロフィール・想いをまとめています。
• お問い合わせ …実験教室のご依頼、執筆・講演の相談、科学監修等はこちらのフォームからお寄せください。