Scientific Method

The Scientific Method is an organised way for scientists (or anyone!) to answer questions and develop solutions. There are usually six parts to it. • Purpose/Question – What do you want to learn? An example would be, “What doorknob in school has the most germs ?” or “Do girls have faster reflexes than boys?” or “Does the color of a light bulb affect the growth of grass seeds?” • Research – Find out as much as you can. Look for information in books, on the internet, and by talking with teachers to get the most information you can before you start experimenting. • Hypothesis – After doing your research, try to predict the answer to the problem. Another term for hypothesis is ‘educated guess’. This is usually stated like ” If I…(do something) then… (this will occur)” An example would be, “If I grow grass seeds under green light bulbs, then they will grow faster than plants growing under red light bulbs.” • Experiment – The fun part! Design a test or procedure to find out if your hypothesis is correct. In our example, you would set up grass seeds under a green light bulb and seeds under a red light and observe each for a couple of weeks. You would also set up grass seeds under regular white light so that you can compare it with the others. If you are doing this for a science fair, you will probably have to write down exactly what you did for your experiment step by step. • Analysis – Record what happened during the experiment. Also known as ‘data’. • Conclusion – Review the data and check to see if your hypothesis was correct. If the grass under the green light bulb grew faster, then you proved your hypothesis, if not, your hypothesis was wrong. It is not “bad” if your hypothesis was wrong, because you still discovered something!

Accuracy A measurement result is considered accurate if it is judged to be close to the true value. Repeatable A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results. Reproducible A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained. Variables These are physical, chemical or biological quantities or characteristics. Categoric variables have values that are labels. Eg names of plants or types of material. Continuous variables can have values (called a quantity) that can be given a magnitude either by counting (as in the case of the number of shrimp) or by measurement (eg light intensity, flow rate etc). A control variable is one which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored. - The dependent variable is the variable of which the value is measured for each and every change in the independent variable. The independent variable is the variable for which values are changed or selected by the investigator.