Maelstrom Lamp
the physics behind it
The lamp harnesses two sets of optical phenomena and combines them to create its visual effects:
The "magic lantern" is a device for projecting images. It has been known for centuries (the first description of it was made in the 15th century) and can be considered the grandad of cinema. Its effect is produced by a lens placed on the side of a box; what is inside the box, if properly lit up, will be projected on the wall that the lantern is facing. The physical phenomena at play in this simple object are: reflection, refraction and projection.
Inside the lantern a physical process takes place, which is called layer interference. This is a natural phenomenon in which light waves reflected by the upper and lower boundaries of a thin film interfere with one another, increasing reflection at some wavelengths and decreasing it at others. When white light is incident on a thin film, this effect produces colorful reflections.