Steps and Terms


The scientist starts with by asking a question. There must be a problem that they want to solve. Let’s take the hypothetical problem of a scientist wondering if fertilizer will make their tomato plants grow taller.


The scientist must then research to see what others have found to be the case. If a study has been done in the past, it does not mean that the scientist should stop. The conditions may be different than they were for previous studies and more data will help future scientists understand the subject.


A hypothesis is what the scientist thinks will happen. It is an educated guess based on research. In the case of our scientist, the hypothesis could be: Adding fertilizer will make the tomato plants grow taller.


The scientist then conducts an experiment. She may put fertilizer on half of her tomatoes. Then she compares them to the other half to see if they grow taller.

Dependent and Independent Variables

In an experiment, there are two types of variable, or things that can be changed. The independent variable is what the scientist does. In this case, the independent variable is the addition of fertilizer. The dependent variable is the effect that the scientist observes. In this case the dependent variable is the height of the tomato plants.

Experiment and Control Groups

In an experiment there should be an experiment and a control group. The experiment group is the group that the scientist acts on, while the control group does not receive the experiment and is used for comparison. In our experiment, the tomato plants that received fertilizer are the experiment group, while the ones that did not are the control group.


After the experiment, the scientist must analyze the results. Was the hypothesis confirmed or rejected? Did the results support previous research?


When reporting scientific findings, the scientist must include all details of the experiment and research that was done. Future scientists will use her reporting when researching for their own scientific problems. In our experiment, details like weather, sunlight, amount of water received, etc. are all important factors when reporting on the experiment.

Scientific Theory

After repeated experiments have proven a hypothesis, a scientific theory is established. That scientific theory is used to predict and explain hypotheses in other situations.








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