Labs / Physics
Prism Dispersion
Drag anywhere to aim the white beam into the prism. Each color bends by a slightly different amount because glass has a higher refractive index for violet than for red — so the beam fans out into a spectrum on the screen. Change the glass, the apex angle, and the incidence to see the rainbow spread and shift.
red δ 0°violet δ 0°spread Δ 0°
What to try
- Push the dispersion slider up. Which color swings the most — red or violet — and why?
- Switch to Diamond. Where did the light go, and what is stopping it from leaving the glass?
- Flip on “single wavelength.” If light were only one color, would a prism make any rainbow at all?
- Widen the apex angle. Does a fatter prism spread the colors more, or less?
- Drag the beam to graze the face at a steep angle. What happens to the whole spectrum as the incidence grows?