Why is the sky blue? How does a rainbow form? What colour does red and blue light make when you mix them? Light is full of secrets — let's reveal them all!
Explore the physics of light with interactive experiments!
White light is actually all colours mixed together — a prism separates them!
Humans can only see wavelengths between 380 and 700 nanometres — that's a tiny slice of all the light that exists! Infrared (TV remotes), ultraviolet (bees can see it!), X-rays, radio waves — they're all the same kind of wave, just at different frequencies.
From tiny gamma rays to giant radio waves — they're all light! We can only see a tiny sliver.
Test your knowledge — 5 questions about light and colour science!
Rainbow physics, light mixing, diffraction, and atmospheric optics
Colours and light simulations use ray-tracing and wave optics to explain the vivid optical phenomena seen in everyday life. Rainbow simulations trace sunlight through millions of spherical water droplets, computing wavelength-dependent refraction angles to produce the primary and secondary arcs and the Alexander's dark band between them. Soap-bubble thin-film interference models compute the path-length difference across a locally varying membrane thickness and sum colour amplitudes to map the swirling violet-green-orange patterns.
Sunset gradient simulations apply Rayleigh and Mie scattering coefficients to a tangential ray path through an exponential-density atmosphere, explaining why the setting sun appears orange-red. Additive-colour mixing simulations demonstrate RGB light combination on a virtual stage, showing how three narrow-band primaries reproduce thousands of perceptual colours. These tools are used in lighting design, film production, and introductory physics courses.
Each simulation in this category is built with accuracy and interactivity in mind. The underlying mathematical models are the same ones used in academic research and professional engineering — just made accessible through a web browser. Changing parameters in real time and observing the results is one of the most effective ways to build intuition for complex scientific and engineering concepts.
Topics and algorithms you'll explore in this category
Common questions about this simulation category