Engelmann's experiment

Engelmann's experiment, conducted in the 1880s, explored how different colors of light affect photosynthesis. He used a filamentous alga and illuminated it with a prism, producing a spectrum of colors. By placing bacteria near the algae, he observed that the bacteria thrived where the algae absorbed the most light—especially in the blue and red wavelengths. This demonstrated that these colors of light were most effective for photosynthesis, highlighting the importance of light quality in plant growth. Engelmann's work laid foundational insights into how plants convert light energy into chemical energy.