Unlock the Magic with a Transparent Tube? See the Law of Energy Conservation in Action! (Also Great for Measuring Gravity!)
I’m Ken Kuwako, your Science Trainer. Every day is an adventure in experimentation!
Objects pick up speed as they fall. It feels like common sense, doesn’t it? But hidden within that simple motion are the grand rules of the universe. Are you ready to unlock the mysteries of “falling objects”?
Today, I want to share an exciting experiment that uses everyday tools to visualize the way invisible energy changes its form right before your eyes.
Capturing Invisible Forces! The “Transparent Tower” Setup
To get started, we put together a setup using a transparent acrylic pipe—50cm tall and 3cm in diameter—which looks a bit like a high-tech magic wand. We picked this up at Tokyu Hands and secured it to a stand to create our very own vertical “experimental tower.”
The secret weapon of this apparatus is the addition of two BeeSpi (speed measurement devices). By dropping a steel ball through the pipe, we can catch its precise speed at two different points. With this simple setup, we can do more than just observe; we can actually calculate the Law of Conservation of Mechanical Energy and even measure gravitational acceleration—the very force with which the Earth pulls us down.
When you gently release the ball from the top, it accelerates under the pull of gravity, zooming through the two timing gates.
Proving Energy’s “Transformation” with Data
For this specific run, we used a pachinko ball with a mass of 0.00545 kg (5.45g). We tracked how the potential energy the ball held at its highest point transformed into kinetic energy (the energy of motion) as it gained speed during the fall.
Take a look at this fascinating data collected and calculated by my students:
The Beauty of the “Error Margin”
In this dataset, we calculated the error rate based on the potential energy at the initial height of 0.60m.
Of course, because of air resistance and tiny amounts of friction against the pipe walls, the numbers never match the “theoretical value” perfectly. However, real science isn’t about finding a perfect textbook answer; it’s about the process of comparing and analyzing your own data.
By testing balls of different sizes and taking the average of five separate trials, the students improved the reliability of their results. Seeing the “average values” stabilize through repetition gave the students a real sense of accomplishment.
A simple phenomenon like “falling” is happening all around us every day. But when you look at it through the lens of numbers, the laws of physics that govern our world start to feel a lot more personal—and a lot more exciting!
Inquiries and Collaborations
I am dedicated to making the wonders of science accessible to everyone! I share easy-to-follow guides and tips for fun science experiments you can try at home. Feel free to explore more:
・ My “Science Hackbook” is now available in print! Check it out here.
・ Learn more about Ken Kuwako here.
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Catch my latest experiment videos on the Science Hack Channel!
４月のイチオシ実験！
- 光の魔法CMYウォーターキューブ：光の魔法を体験せよ！水を注ぐと新たな立方体が出現する魔法のような実験です。
テレビ番組・科学監修等のお知らせ
- 4月9日（木）「THE突破ファイル」（日本テレビ ）の科学監修を行いました。夜7時〜となります。
書籍のお知らせ
- サクセス15 ４月号にて、野球の科学について記事を執筆しました（2026/3）
- 『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。
講師・ショー・研究等のお知らせ
- 3/20（金） 日本理科教育学会オンライン全国大会2026「慣性の法則の概念形成を目指した探究的な学びの実践」について発表しました。
- 6/14（日） 千葉大学インスタレーション「探究」にて講師を務めます
- 7/18（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。
- 10/10（土） 秘密兵器「帯電ガン」が炸裂！ビリビリ！ドキドキ！静電気サイエンスショー＠千葉市科学フェスタ（午後予定）
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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。
- Reveal the True Nature of Sound! Experience the Magic of Wave Science and Visualization with GeoGebra
- Unlock the Magic with a Transparent Tube? See the Law of Energy Conservation in Action! (Also Great for Measuring Gravity!)
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- A Magic Trick to Keep Your Cake Spotless! The Surprising Science Behind “Frozen Candles” (Melting & Boiling Points of Paraffin)
- Not a Broadleaf Tree?! The Truth Behind Ginkgo’s Fan-Shaped Leaves—A Living Fossil Revealed (Plant Guide)
- A Split-Second Miracle! Capture the “Law of Inertia” Hidden Inside a Water Balloon!
- The Moment Play Turns into Learning! The “Magic of Math” Hidden in Spirograph Patterns (Desmos Programming)
- Visualize Invisible Electric Potential in 3D! An Amazing Science Craft Using a Lunchbox Lid
- Shadows Reveal Physics Secrets! The Surprising Link Between Uniform Circular Motion and Simple Harmonic Motion
