Experiment
Thin-Film Interference
When white light hits a thin film — a soap bubble, an oil slick — some wavelengths interfere constructively and others destructively. The result: iridescent color that shifts with thickness. Drag on the film to sculpt its surface and watch the physics of light play out.
thin film
Reflected spectrum at cursor
Thickness profile (cross-section)
Color vs thickness
Physics: Path difference = 2nt where n is refractive index and t is film thickness.
Constructive interference when 2nt = (m+½)λ (with phase shift at one surface).
Brush radius
30
Refractive index
1.33
Viewing angle
0°