Sunset Experiment
Purpose
Demonstrates Rayleigh scattering (\(I \propto 1/\lambda^4\)) using a colloidal suspension in water. As particle concentration increases, short wavelengths scatter out of the beam (water turns blue) while the transmitted light shifts from white to yellow to orange to red -- directly modeling why the sky is blue and sunsets are red.
Figure 1:
Progressive addition of silica suspension. Top: clear water, white transmitted light. Middle: water turns blue from scattered short wavelengths, transmitted spot yellows. Bottom: strong blue in tank, transmitted light turns orange-red.
Equipment
- 1