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

It’s a cold, dry winter day. You reach for the doorknob, and suddenly a sharp pain shoots through your fingertip. ZAP! You can almost see the spark. It feels like a tiny bolt of lightning fired straight from your own hand. We’ve all been there. But did you know this classic winter misery can be fixed with nothing more than a single safety pin?

“Just pin a safety pin to your sleeve and you’ll never get static shocks”

Is that really true? And if it is, what’s actually going on inside our bodies? As a science teacher, my curiosity got the better of me, so I put it to the test!

Does a safety pin really stop static electricity? Time to experiment!

To get to the bottom of this rumor, I brought out two secret weapons from my lab: a “charging gun” and a “charging chair.” With these, we can turn invisible static electricity into numbers (voltage) we can actually see.

First, let’s measure the baseline with no countermeasures at all. I sat in the charging chair and zapped myself with the charging gun…

The voltage built up in my body shot past 18,000 V (volts)! Considering that a household outlet is only 100 V, that’s an outrageous number. The current in static electricity is extremely small, so it isn’t life-threatening, but in terms of voltage alone, my body was storing the energy of a “mini lightning bolt.”

In this state, if I had reached for a doorknob, the electricity would have jumped across with a snap before I even touched it.

Next, still fully charged, I gently brought my sleeve cuff close to a desk. This recreates what we all do without thinking in daily life: brushing against furniture or walls. The voltage dropped to around 13,000 V. So a little bit of electricity was escaping through the fabric.

In other words, touching a wall before you touch the doorknob really does help. Gas stations have a spot for exactly this reason, don’t they?

And now, the star of the show. I attached a metal clip (standing in for a safety pin) to my cuff and let it touch the desk. The result was a real surprise.

In the photo, I’m using a bulldog clip to make it easier to see.

The peak voltage plunged to 9,000 V in one go! And when the clip was pressed firmly against the desk, it dropped even further, down to 5,000 V.

What’s even more striking is how fast the charge drains away. Without metal, the voltage barely budged. Add a piece of metal, and it slid downward smoothly. This is clear proof that “the safety pin gives the electricity an escape route, so high voltage can’t build up in your body.” The rumor was 100% true!

Why a safety pin? The big job of a tiny piece of metal

So why does one little safety pin work so well? The secret lies in how easily metal conducts electricity.

That painful “ZAP!” happens when built-up electricity rushes out all at once from a single spot. But if you have a safety pin on your sleeve, every time you pass near a desk or a wall, the metal acts as a bridge and lets the electricity “quietly leak away, little by little.” Think of a dam: instead of waiting for it to overflow and burst, you keep a small drain open so the water trickles out all the time.

I also explained this on the TV show “Arienai ∞ Sekai” (TV Tokyo), where I appeared as the science supervisor. As we showed on the program, wearing a metal watch or bracelet works too. You can even find anti-static wristbands at 100-yen shops.

Old wisdom meets modern science

In fact, this principle has been put to use around us for a long time. Take the “lightning rod” on top of a building. It’s a device that safely sends the enormous static electricity of lightning down into the ground. Older cars were also often seen with a rubber strap called an “earth belt” dangling to the ground. It let the static that built up in the car body while driving drain into the road, doing exactly the same job as our safety pin.

And here’s another fun one: I once ran an experiment where I put staples into the soles of my shoes. That worked for the same reason. The metal grounded me to the floor, which prevented static buildup.

靴にホチキスの針を刺したら静電気が5000Vも減った！中学生が都市伝説をガチ検証【科学監修】（THE突破ファイル）

From a tiny safety pin to a giant lightning rod to the clever tricks of old cars, science keeps quietly protecting our everyday lives in different forms. If you’re dreading those fingertip zaps this winter, try tucking a safety pin inside your sweater as a little good-luck charm.

References

・Explained on “Sata Pura” (MBS), broadcast on Saturday, October 31, 2026.

【監修・出演】そで口に安全ピンをつけると静電気が逃げる? サタプラ（TBS）

・Explained on “Arienai ∞ Sekai” (TV Tokyo), broadcast on Tuesday, January 6, 2026.

静電気が起こりにくくなる裏ワザ「ありえへん∞世界」（テレビ東京）【科学監修・出演】

Contact and Requests

Making the wonders and fun of science more familiar! This site collects fun science experiments you can do at home, along with tips to make them work. Try searching around!
・The contents of “Kagaku no Netacho” (Science Idea Notebook) are now a book! Details here
・Learn more about the site’s author, Ken Kuwako, here
・For all requests (writing, lectures, science workshops, TV supervision and appearances, etc.), click here
・Get article updates on X!

Kagaku no Neta Channel (Science Idea Channel) features experiment videos!

テレビ番組監修・イベント等のお知らせ

• 「ネイチャーティーチャー」（TBS）に出演しました。Tverにて11月3日（火）まで配信中です。

• サタプラ（MBS）にて「日常に潜む！ピンチ脱出法について」のコーナーに出演しました。Tverにて11月7日（土）まで配信中です。

• 11/4（水）ZIP（日本テレビ）のコーナー（7:20分ころ放送予定）にて科学監修を担当しました。ゴンチャのストローの差し方に関するウラザワと科学解説についてです。

• 11月27日（金）　テレビ監修番組放送予定
• 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

１１月のイチオシ実験！

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書籍のお知らせ

• 『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。
  

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