Why Does Light Shake? The Hidden “Fleming’s Left-Hand Rule” Inside a Stylish Lamp (Edison Bulbs & Vibra Lamps)

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

【This article is also available on Radio!】

Imagine you’re relaxing at a cafe when you notice a light bulb nearby. Suddenly, it starts swaying and dancing like a living creature. Would you be able to spot the “scientific trick” hidden behind its mysterious movement?

Today, we’re diving into the story of “vibration” woven by light—from Thomas Edison’s passion that lit up the world 150 years ago to a playful bulb I discovered in a modern interior shop.

The Bamboo that Lit the World: The Story of the Edison Bulb

Let’s start at the very beginning: the Edison bulb. I recently captured a video of a precious original model on display at the National Museum of Nature and Science.

Did you know this light bulb has a deep connection to Japan?

Back when gas and arc lamps were the norm, people dreamed of a safer, easier way to light their homes. That’s when the legendary inventor Thomas Edison focused on the filament—a material that glows when electricity passes through it in a vacuum.

Edison searched desperately for a material that wouldn’t burn out quickly, testing thousands of plants from all over the globe. The “ultimate material” he finally discovered was none other than bamboo from Kyoto, Japan.

By placing thin bamboo strips in a crucible and heating them intensely at temperatures between 800 and 1,000 degrees Celsius, he created bamboo filaments. These were incredibly durable and played a massive role in making light bulbs practical for everyone. It’s amazing to think that the glow illuminating the nights of the late 19th century was supported by Japanese bamboo!

Why is the Lamp Dancing? The Secret of the Vibra Lamp

Fast forward to the present day. At an interior shop near Suidobashi Station, I encountered a fascinating bulb. The light inside was flickering and swaying just like a candle flame.

It’s called a Vibra Lamp. I was so intrigued that I got permission from the shop to film it and “dissect” its scientific mechanism.

Vibra Lamp (Amazon)

The Magic of Electricity, Magnetism, and Force

So, why is this filament dancing? If you look closely at the video or photos, you’ll see a tiny black object at the base of the swaying filament.

That black object is actually a magnet. When you bring “electricity” and “magnets” together, a famous law from science class kicks in: Fleming’s Left-Hand Rule!

When an electric current flows through the filament in a magnetic field created by the magnet, a “force” is generated. This is the exact same principle that makes motors spin. But here’s the clever part: the electricity from our wall outlets is Alternating Current (AC). AC switches its direction at a staggering speed—50 or 60 times every single second.

As the direction of the current flips, the direction of the force (thanks to Fleming’s rule) flips along with it. As a result, the filament is pulled back and forth rapidly, appearing to our eyes as a gentle, dancing vibration. It’s a stylish and scientific use of the very nature of AC electricity!

Vibration Power: A Hidden Hero in Your Home

This “AC vibration” is actually working in many products around you. Take, for example, the air pump used in fish tanks. Inside, there’s a coil and a magnet. The magnet vibrates in sync with the rhythm of the AC, driving the pump to create those familiar bubbles.

The Master of Rhythm in Science Class

Remember the spark timer (recording timer) from the science lab? That click-clack sound as you measured the movement of a cart? That device also uses the precise rhythm (frequency) of the AC from the outlet to mark dots exactly 50 or 60 times per second.

The electricity we use so casually is actually “pulsing” back and forth dozens of times a second. The Vibra Lamp takes that invisible pulse and transforms it into a beautiful dance of light.

Next time you’re at home, try to find other appliances that “vibrate.” You might just find a scientific drama hidden there that would even surprise Edison!

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