Biology Lab (continued)

Results from our photosynthesis lab were mixed. In a lot of cases, both test tubes turned blue. This is easy to explain, since in both treatments a living plant was placed in the bromothyl blue solution. Plants use carbon dioxide for photosynthesis. As carbon dioxide is used by the elodea plants in the test tubes, the BTB solution gradually turned from yellow back to blue. We hypothesized that if we surrounded one of the tubes with foil then photosynthesis would stop and the BTB solution would stay yellow (since the carbon dioxide wasn't being absorbed). For many of the groups, this wasn't the case...photosynthesis still occurred in spite of the darkening treatment. The question now becomes what other changes could we make that might keep photosynthesis from happening, or might give us the results that we expect?

There were several groups, however, that did observe results that supported their hypotheses. The darkened tube still had a yellowish tint to it, while the tube in the light was completely blue.

This illustrates two important points: First of all, failure of results to support a hypothesis is NOT failure of the experiment or of the scientific process. As long as we are able to look at our results critically, learn from them, and use them as a springboard for new testing, then this can actually be one of science's greatest moments. We're going to learn in the next couple of weeks about a man named Oswald Avery who, although he never achieved the results that he dedicated his life to, managed to make one of the most profound conclusions in the history of biology.

The second point here is the importance of repeated trials. By having many groups doing the same experiment, we were able to get data and record observations as a class that gave us a much better idea of what was happening in those tubes than we would have been able to by looking only at any one group.