What is wrong with this experiment? In 1668, Francesco Redi did a series of experiments on spontaneous generation. He began by putting similar pieces of meat into 12 identical jars. Four jars were left open to the air; four were sealed, and four were covered with gauze (the gauze will exclude the flies while allowing the meat to be exposed to air). In both experiments, he monitored the jars and recorded whether or not maggots (young flies) appeared in the meat. In both experiments, flies appeared in all of the open jars and only in the open jars. This experiment is a well-designed experiment and has nothing wrong with it. The experiment does not have a question. This experiment does not have a control group. There was no dependent variable.
The Correct Answer and Explanation is:
The correct answer is: There was no dependent variable.
In scientific experimentation, a dependent variable is the measurable outcome that is observed and recorded to determine the effect of different conditions. In Francesco Redi’s 1668 experiment, the purpose was to investigate whether maggots appear on meat spontaneously or only when flies have access to it. He used three different types of jars: uncovered, sealed, and covered with gauze. While this setup effectively addresses the hypothesis and includes controls, the original description of the experiment fails to clearly define a measurable outcome that serves as a dependent variable.
A proper dependent variable would have been the number of maggots observed in each jar after a set period of time. However, the description mentions only a binary observation—whether maggots appeared or not. This approach limits the experiment’s precision and depth. A dependent variable should ideally allow for quantitative analysis to make stronger conclusions.
This omission is significant because it restricts the ability to analyze variations or trends across different treatments. Without a defined dependent variable, the results cannot be objectively measured or statistically validated. It reduces the experiment to a qualitative observation, which was acceptable in Redi’s time, but does not align with modern standards of experimental design.
That said, Redi’s experiment was groundbreaking. He systematically challenged the idea of spontaneous generation and provided one of the earliest known uses of controlled experimentation in biology. His design included experimental and control groups and provided compelling evidence that flies were necessary for the development of maggots. While the concept of a dependent variable had not yet been formalized, the lack of one by today’s standards represents a weakness in the experiment’s structure, particularly from a modern scientific viewpoint.
