Jan Baptista van Helmont was a Flemish chemist and physician during the 1600’s. He studied various things, but is known for his experiments related to spontaneous generation theory. Spontaneous generation theory stated that living things came to life from non-living matter. For example, fleas could come to life from dust. Van Helmont created an experiment to test his hypothesis that sweat provided the “active principal” which brought mice to life from dust. To test this, he put a sweaty shirt and grains of wheat into a box and waited to see if mice were spontaneously produced. Every time he conducted his experiment, mice appeared to be chewing their way out of the box within 21 days. Based on the description of his experiment, did van Helmont set up his experiment correctly to follow the scientific method? Support your claim with evidence and explain your reasoning.

No, he did not set up his experiment correctly to follow the scientific method  

Explanation:

The scientific method is a research method used to produce knowledge. It consists of systematic observations, measures, experimentation, analysis, and verification of a hypothesis. It is based on two aspects: reproducibility (which is the capability of reproducing the experiment in any other place by any researcher) and refutability (which is the susceptibility to be refused). This scientific method needs to be replicable. Replication refers to the need to repeat a research study, under different situations, different subjects, and with different researchers, to determine the safety of the original findings and their possibility of generalizing them to other groups and participants.  

There are different steps to follow in a scientific method:

Previous knowledge about the study objectDefinition and problem statement. The question for which there is not an answer yet.The goal, which is what the investigator wants to know.  Hypothesis formulation. The conjecture that the investigator makes in order to predict what is going to happen.  The methodology of the experiment: Data collection and analysis. This step involves testing the observations. Results The data obtained during the experiment and presented as graphs, tables, diagrams, or description. Discussion: Where the obtained results are explained and compared with other similar studies.   Conclusions and Verification of hypothesis: The hypothesis is accepted or rejected. The section also includes the comparison of expected results with observed results. The closure of the experiment.

Van Helmont experiment:

Previous knowledge: It seems to be missing previous information about the experiment and the species involved in it. Definition and problem statement: Do living things come to life from non-living matter? The goal: analyze if there exists a spontaneous generation in species such as mice from a non-living element. Hypothesis formulation: Sweat provides the “active principle” which brings mice to life from dust.  Methodology: He put a sweaty shirt and grains of wheat into a box and waited to see if mice were spontaneously produced. He conducted the experiments many times and got to observe mice within21 days. The independent variable was the sweaty shirt and grains. Placing a sweaty shirt would be the treatment, but he failed in having a control group. The control group would have had only grains, but no shirt. The control group is used to identify if there are any other factors (other than the shirt) influencing the results obtained in the study. Data from an experimental group are compared with the data from a control group. Now we know that the controlled variables of this experiment (grain and box), were actually independent variables because they were used as sources of food and shelter for the mice. Results Mice observation within 21 days

Apparent competition occurs when two individuals that do not directly compete for resources affect each other indirectly  by being prey for the same predator. Consider a hawk (predator, see below) that preys both on squirrels and mice.  In this relationship, if the squirrel population increases, then the mouse population may be positively affected since more squirrels  will be available as prey for the hawks. However, an increased squirrel population may eventually lead to a higher population of hawks  requiring more prey, thus, negatively affecting the mice through increased predation pressure as the squirrel population declines. The opposite effect could also occur through a decrease in food resources for the predator. If the squirrel population decreases,  it can indirectly lead to a reduction in the mouse population since they will be the more abundant food source for the hawks.  Apparent competition can be difficult to identify in nature, often because of the complexity of indirect interactions that involve  multiple species and changing environmental conditions.