The Scientific Method
Cause and Effect
Scientists observe everything in the world from the viewpoint of cause and effect. There is no magic!
Scientists believe that all events are the result of a collection of other earlier events. Take a split-second. Watch something happen, like fireworks exploding, an alarm clock starts ringing, or a leaf twisting in the breeze. The events that happened before the split-second that you watched are the "causes". The single-event that you saw during the split-second is called the event". With the help of your family or classmates, pick a single, split-second event. Try to name twenty or so other split-second events that helped cause it.
The Scientific Method
Each collection of causes will produce a predictable event. Gaining new knowledge about our world is simply understanding how and why the causes create a particular event. Over the years, scientists have developed a step-by-step method to investigate an event. It is called an “experiment”. If care and honesty are used, the scientific method should help you study your experiment. You should be able to discover the correct cause-and-effect relationships. The following steps will lead you through the scientific method:
A. Pick a Topic
Before an event can be studied you must have some idea of what it is that you want to observe. Your topic might be "acid rain".
B. Limit Your Topic
You have very little time and resources. You will only be able to study an extremely small collection of events. You must, therefore, limit your experiment to one or two specific events. "I will study the effect of nitrate-bearing acid rain on a brick."
C. Study, Observe and gather
Visit your public library or the Internet and read about your limited topic. Observe related event. Gather existing information concerning your limited topic. Look for unexplained or unexpected events or results. Also, you should learn something about the field of mathematics known as statistics, to best present your data.
Organize what you know about your topic. Make lists of known causes for specific events. Describe what generally happens when you observe related events. Pick a question that can be answered. No experiment can tell you "Why is there air?". You can find out "What happens to plants if they don’t get air?". Pick a topic that interests you and that is within your technical expertise. No one expects a nuclear reactor from an elementary student.
If you build a device such as a laser, be sure to do an experiment with it. Just constructing the device does not constitute an experiment and will not be judged highly.
E. Hypothesize, form a question and predict
Write a sentence that predicts what will happen if you do your experiment. This statement is called a "hypothesis". Your theory must agree with observations already studied. From your theory, put together the exact question that you want to answer with your experiment. State what you think would happen if some of the causes of your event were changed. Causes that can change are called "variables". Some variables are turned on or off like a light switch; others change in size like the temperature setting of an oven.
Design and do a series of experiments. You must design each experiment so you can observe the results if one and only one variable is changed. By changing just one variable, you can determine that variable’s effect on your chosen event. To see the real effect, you need to change the size of a single variable several times. Be sure to include one or more experiments when none of the variables are changed on purpose. This is called the control experiment. The control is very important. It shows the normal results from your experiment if you don’t try to change anything. Be careful, you may be able to keep many variables from changing, but some you usually can’t do anything about. Some variables you have control over are room temperature, time of day, how far you stretch a spring, relative humidity, and how hungry your human or animal subject is. Some variables that you can't do anything about are atmospheric pressure, how bright the sunshine is, or the mood, skill, reflexes, or previous dietary habits of you and/or your subjects.
G. Examine Your Result
Did your experiments give you the expected results? Why or why not? Be very honest! Reexamine your experiments. Was more than one variable changed at one time? Was your experiment done with the exact same steps each time? Are there other causes that you had not considered or observed? Were there errors in your observations? How large were the errors? If your physical skills were involved, how much better did you get at your job with each repeat? Remember that understanding errors and reporting that a suspected variable did not change the results can be valuable information. If time permits, repeat your experiment several times, see if you get the same results every time.
H. Draw Conclusions
What variables are important? Was your hypothesis correct? Did you collect the proper data? Did you collect enough data? Does more work need to be done or is your experiment finished? If your hypothesis didn't predict the correct result, that is okay, you just learned something you didn’t expect.