2026年4月26日 / Last updated : 2026年4月26日 桑子 研 Science

Turn Your Phone into Magic Eyes! The Mind-Blowing World of Visualizing Heat for $400 (FLIR ONE Pro)

This is Kuwako Lab, your science trainer. Every day is an experiment.

Did you know that our world is filled with “light” we can’t even see? What would reality look like if we could capture that invisible light? Until just a few years ago, the equipment needed to do that cost thousands of dollars. Now, it fits in your pocket and is surprisingly affordable. Today, I’m sharing an excited experiment report from a science teacher who got their hands on this “magic eye.”

A high-performance thermal camera in the palm of your hand

Thermal imaging cameras that visualize heat (mid- to far-infrared) are now available for around 50,000 yen. Not long ago, these were specialized tools reserved for research institutions, costing orders of magnitude more. The pace of technological progress is astonishing.

Even better, you can use this camera simply by plugging it into your smartphone’s Lightning or USB-C port.

FLIR one PRO（Amazon）　Rakuten

Seeing the “heat” radiating from the human body

Let’s attach the infrared camera to a smartphone and take a picture of a person. What you see is a completely different world.

Areas of exposed skin appear red, clearly indicating higher temperatures. Now look closely at the glasses. They appear cooler, almost bluish, compared to the surrounding skin. This happens because the lenses absorb and reflect the infrared radiation emitted from the body.

Our bodies are constantly radiating invisible infrared light, but materials like glass block it. That’s why the glasses stand out.

When infrared radiation hits the sensor, it knocks electrons loose depending on its intensity. By analyzing the number of emitted electrons, the device assigns colors—red for warmer areas and blue for cooler ones—turning heat into something we can actually see.

The “trail of heat” drawn by an eraser

With this camera, even everyday actions reveal hidden energy changes. Try rubbing an eraser on a desk.

This is where things get really fun!

To the naked eye, nothing changes. But through a thermal camera, invisible energy suddenly becomes visible. Watch what happens when an eraser is rubbed across a desk:

Scrubbing the surface back and forth…

Now look through the thermal camera…

Heat generated by friction appears as a bright streak across the desk.

Catching the heat of an explosion: the paper cup rocket

Next, let’s observe chemical energy in action. This experiment involves spraying alcohol into a can, sealing it with a paper cup, and igniting it to create a “paper cup rocket” (see details here).

The flame from burning alcohol is almost invisible in a bright environment. But with thermal imaging, the intense spread of heat during the explosion becomes crystal clear. You can even see the temperature rise of the empty can afterward, showing an increase in internal energy.


Where does the energy go? The lead ball experiment

You’ve probably learned about the law of conservation of energy in physics. Here, we actually demonstrate how kinetic energy transforms into heat through friction.

Place a heavy lead ball inside a capsule toy and roll it down a slope. Because the center of gravity shifts, the capsule rolls slowly.

Here’s the temperature before rolling:

Now let’s roll it:

Since the capsule rolls slowly, the kinetic energy it should have gained is instead being converted into other forms through friction. After rolling it three times, here’s the result:

The temperature rises by about 1 degree. The reddish areas around it are just traces of my body heat from touching it, so don’t mind those.

Interestingly, I first tried this experiment with a steel ball, but steel has a relatively high specific heat, making temperature changes hard to detect. So I ordered lead, which heats up more easily, and tried again. The effort paid off.

Revealing the hidden world of living creatures

This camera is also great for observing animals. When pointed at cold-blooded creatures like frogs or lizards, they almost disappear into the background. Since their body temperature matches their surroundings, they blend right in from the camera’s perspective.

Thermal imaging isn’t just cool—it’s a powerful tool for understanding scientific concepts like heat and energy in a very intuitive way. I was so fascinated that I ended up buying one myself, out of pocket. I haven’t told my wife how much it cost… but honestly, being able to share this sense of wonder with my students makes it completely worth it.

By the way, this camera detects mid- to far-infrared light, but near-infrared—like the kind used in remote controls—can actually be captured with your regular smartphone camera. This experiment is also a lot of fun, so give it a try.

[https://phys-edu.net/wp/?p=24304](https://phys-edu.net/wp/?p=24304)

Contact and inquiries

Bringing the wonders of science closer to everyday life. I share fun experiments you can try at home, along with easy-to-understand tips. Feel free to explore!

・The content from this blog has been published as a book. Learn more here
・About the author, Kuwako Lab: here
・For requests (writing, lectures, workshops, TV supervision, appearances, etc.): here
・Updates are shared on X

Science Channel features experiment videos!

４月のイチオシ実験！

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） スクリーンショット 2014-07-05 0.43.51
  • 『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

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。
 
Categories
Science
Science

Previous article

Shocking Truth: Can Humans Conduct Electricity? Let’s Try the Human Circuit Experiment! [Tamesu-kun]New!!
2026年4月24日