Unlock the Rainbow: How to Make a Magical “Spectroscopy Mask” and See the Universe’s Hidden Code

I am Kuwako Ken, your Science Trainer. Every day is an experiment.

The “light” we see every day—wouldn’t it be exciting to learn that its true identity is actually a magnificent bundle of rainbows, made up of many colors?

In this article, I’ll show you how to make a magical “Spectroscopy Mask” that lets you peek into the beautiful world hidden inside light, along with the scientific secrets behind it. This is a fun and educational science craft modeled after Fukuoka’s unique souvenir, the “Niwaka Senpei” (a traditional cracker)!

The True Identity of Light: A Rainbow?

Sunlight and light from a bulb look like a single white or yellowish color at first glance, don’t they? However, that light is actually a complete mixture of all seven rainbow colors: red, orange, yellow, green, blue, indigo, and violet. The process of separating this light into its color components is called dispersion (Bunko), and the resulting band of colors is known as the spectrum. The reason we see a rainbow after the rain is that tiny water droplets in the air act as prisms, dispersing the sun’s light.

This time, we’ve made a mask using the magical item, the “Diffraction Sheet”, which lets you easily experience this phenomenon of “dispersion”.

Let’s Make a Spectroscopy Mask from “Niwaka Senpei”!

The motif for our mask is the super cute, droopy-eyed “Niwaka Senpei” cracker, a famous souvenir from Fukuoka. By utilizing its humorous expression, all you have to do is cut out the eye holes and paste the Diffraction Sheet over them—and voilà! Your original spectroscope is complete! Put this on and peek at the world; your everyday view instantly transforms into a fairytale land of rainbows.

I tried drawing various patterns on the mask, but the grasshopper design combined with the face mask turned out to be particularly funny.

The original template data for the mask is available here, so please feel free to download it and create your very own Spectroscopy Mask!

Let’s Observe Different Kinds of Light!

Once you have this mask, you’re officially a “Light Detective.” Let’s observe the spectrum of various lights inside your home and around town.

I tried looking at the sunlight through my smartphone camera, and it was incredibly beautiful. Sunlight appeared as a “continuous spectrum”, where all the colors seamlessly blend together.

⚠️ WARNING! ⚠️

NEVER look directly at the sun with your naked eye or through a smartphone camera. This poses a risk of damaging your eyes. When observing, make sure to stand in the shade or look at the light through a window from inside a building.

A continuous spectrum is visible because high-temperature objects, like the sun, emit light across all wavelengths. The light from incandescent bulbs also shows a beautiful continuous spectrum. On the other hand, what happens when you look at light from fluorescent lamps or neon signs? You will likely see bright “lines” arranged sporadically, unlike the sun’s smooth spectrum. This is called a “line spectrum”, and it acts like a “light fingerprint,” indicating that the light is being emitted by specific atoms.

By analyzing these light fingerprints, scientists can even determine what elements exist in distant stars! It’s quite romantic to think that a simple Spectroscopy Mask connects to the vast field of astronomy, unlocking the mysteries of the universe. Please, use your own Spectroscopy Mask to embark on an adventure to find the “fingerprints” of the light around you.

Contact & Requests

Make the wonders and fun of science more accessible! We compile fun science experiments you can do at home and clearly explain the tricks behind them. Feel free to search for more!
・The content from the Science Notebook is now available as a book. For details, click here.
・To learn more about the operator, Kuwako Ken, click here.
・For various requests (writing, lectures, science classes, TV supervision/appearances, etc.), click here.
・Article updates are delivered on X (Twitter)!

Experiment videos are available on the Science Notebook Channel!

２月のイチオシ実験！梱包材で遊ぼう！

• 静電気の時期になってきました。子供と一緒に梱包材で盛り上がろう！→ やめられなくなる！静電気実験２０

体中に梱包材をはりつけてみよう！

テレビ番組等・科学監修等のお知らせ

• 「月曜から夜更かし」（日本テレビ）にて科学監修・出演しました。

書籍のお知らせ

• 1/27 『見えない力と遊ぼう！電気・磁石・熱の実験』（工学社）を執筆しました。
• サクセス15 ２月号にて「浸透圧」に関する科学記事を執筆しました。
• 『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。

講師等・ショー・その他お知らせ

• 2/20（金）「生徒の進学希望実現支援事業」研究授業＠福井県立若狭高等学校　講師
• 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」について発表します。B会場 第３セッション： 学習指導・教材（中学校）③　11:20-12:20
• 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）　サイエンスショー予定
• 各種SNS　X(Twitter)／instagram／Facebook／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。