This simple experiment was sparked by our experiment "Does cooled water affect aglae growth?" We knew algae needed light to grow, and so we placed our experiment and control cups on our window sill to take advantage of the spring sun. All the windows but one have a reflective film on them to keep the room cooler. Some of the cups were protected by the film and some were not. We had broken our protocol, as we had introduce another variable (inconsistent light intensity)by mistake.