# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DZsUjFoAyHq
- **Gondola URL:** https://gondola.cc/posts/66891680-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/d15a3ed885.jpg
- **Posted:** 2026-06-17T15:47:27.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

Floating lamps look like a single trick. They’re actually two separate physics problems stacked on top of each other, and neither one is just a magnet pulling the lamp up.

Problem one is staying airborne. You can’t levitate anything with fixed permanent magnets alone. Earnshaw’s theorem proves it: no arrangement of static magnetic fields can hold an object in stable equilibrium. Nudge it off-center and it either snaps to the magnet or flies away. There’s no stable pocket to sit in.

So these lamps cheat with active stabilization:

	•	A Hall effect sensor in the base tracks the floating magnet’s exact position
	•	A microcontroller reads that position thousands of times per second
	•	An electromagnet adjusts its field strength in real time to counter every drift

Rise too high and the field weakens. Drop too low and it strengthens. The lamp isn’t resting on anything. It’s being caught and re-caught continuously by a feedback loop running far faster than your eye can register.

Problem two is power. A levitating lamp still has to light up, and you can’t run a wire to something hovering in air. The answer is electromagnetic induction:

	•	A transmitter coil in the base drives a high-frequency alternating current
	•	That oscillating field induces a voltage in a receiver coil inside the lamp
	•	Faraday’s law does the rest: a changing magnetic flux generates EMF, EMF drives current, current lights the LED

Tuning both coils to the same resonant frequency sharpens the coupling, letting usable power jump the air gap with surprising efficiency.

The float and the glow are one magnetic field quietly doing two completely different jobs.

#stemantics #physics #electromagnetism #maglev #engineering

## Stats

- **Views:** 2,889
- **Likes:** 138
- **Shares:** 0
- **Comments:** 2

## Tags

engineering, electromagnetism, physics, maglev, stemantics

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