The Scientific Method

Steps of the Scientific Method Problem/Question Observation/Research Formulate a Hypothesis Experiment Collect and Analyze Results Conclusion Communicate Results

Problem/Question Develop a problem or question that can be solved through experimentation. Example: Is yeast alive? Does it exhibit a characteristic of life? Does is metabolize food when present?

Observation/Research Make observations and obtain background information on your topic. Find out if anyone else has conducted a similar experiment, and what their results were.

Do you remember the next step?

Hypothesis Predict a possible answer to the problem or question. It is a relationship of the independent and dependent variable. If, then… Independent Variable The variable that the experimenter changes, “I” change. Dependent Variable The variable that may change because of the independent. Example: If I add fertilizer to the plant, then the plant will grow faster. If I provide yeast with food, then the yeast will metabolize the food and produce a gas.

Experiment Develop and follow a procedure. Include a detailed materials list. Do multiple trials. Every experiment has a control group and an experimental group. Control- this is the group that has no change, it serves as the standard for comparison. Ie. In the yeast lab we did not add sugar to the control group. Experimental-this is the group that changes

Collect and Analyze Results Modify the procedure if necessary. Confirm the results by retesting Include tables, graphs and drawings. If you use a line graph: The independent variable goes on the x-axis The dependent variable goes on the y-axis If I add fertilizer to the plant, then the plant will grow faster. Plant growth Amount of fertilizer added

Conclusion Include a statement that accepts or rejects the hypothesis. Ie. Our hypothesis was upheld. Yeast produces a gas in the presence of a food source, therefore yeast is alive. Explain possible sources of error. Ie. We may not have poured enough yeast in all the bottles, which is why the balloons did not inflate, and no gas was produced. Make recommendations for further study or improvements.

Any Questions?

Questions/Observations Predictions and Hypotheses Experimentation Some hypotheses are rejected. Some hypotheses are supported. Related hypotheses are verified by many. Theory If a hypothesis has been tested and confirmed many times by many scientists, it becomes a theory. A theory is not a fact. The possibility always remains that future evidence will cause a scientific theory to be revised or rejected.

The Vitruvian Man Theory: From fingertip to fingertip, the span of a person’s arms is equal to his/her height.