Organizing and Conducting a Science Fair Project (continued)

Experimenting

Your project should include controlled experimentation. In other words, if your experiment is done under carefully controlled conditions, what will happen? You, as the experimenter, will change certain conditions and observe how the condition of your subject is affected or changed. This experimentation provides a method for testing your hypotheses.

Your experimental design depends upon the experimentation that you are doing. Bacteria, mice or human beings will require different equipment and procedures than motors, soil and the weather. Whatever the experimentation or the subjects you use, there will probably be many variables. Two types of variables encountered in simple controlled experiments are:

1. INDEPENDENT VARIABLE

The experimenter changes something to observe what will happen. The "thing" changed is the independent variable.

2. DEPENDENT VARIABLE

These "things" that were changed caused something else to happen. The "something else" is the dependent variable.

For example, if the independent variable is the differing amounts of chemical fertilizer added to experimental groups of plants, then a dependent variable would be the difference in height between the experimental groups of plants.

Results -- What Happened?

What do you do with the data that you collect during the experimentation? Well, if your observations are in words, organize a neat log or charts. If your results are in numbers, organize the data in tables and graphs.

Of course, there are many ways to construct tables and graphs. Certain types will serve best for your data. Your teacher may be able to help you decide on what types of tables and graphs to use.

Drawing Conclusions

Once you have completed your experimentation and have collected data, what have you proved? Before you answer that question, consider that data is not always reliable. If you worked with bean plants, for instance, how do you know that all bean plants are exactly like your sample? The answer is, "You don't know." You can only predict or infer that the rest are like your sample. The probability of your sample resembling the total population is not very high if you used five bean plants in each group.

One way to increase the probability, then, is to test a large sample. Fifty, one hundred, or even one thousand bean plants would increase your ability to predict. As a further step, you could have more than one experimental group with each group receiving a different amount of fertilizer. This method would give you even more significant results.

Scientists use statistics to analyze the data collected in an experiment. A statistical treatment of data allows them to predict, or generalize, about larger populations. If you can find someone trained in statistical methods, ask for help in analyzing your data.

You must be careful when drawing conclusions. If someone else repeated your experimentation, would they get the same results? Look over your data. Study it. Do a statistical analysis if you can. Then you can say what you think your experiment shows or seems to indicate.

Your data will either support your original Hypothesis or it will not. You must state this in your conclusion.

Be especially careful that your conclusion is not a new Hypothesis. Any new Hypothesis must be tested.

Writing Your Research Paper

The value of scientific investigation would be lost if it were not reported to others. You have the opportunity to report your study in three ways: a scientific research paper, an exhibit and an oral presentation. At this point, we will consider the writing of your scientific research paper.