The Scientific Method The scientific method is a way to ask and answer scientific questions by making observations and doing experiments.
Overview of the Scientific Method The scientific method is a process for experimentation that is used to explore observations and answer questions. Scientists use the scientific method to search for cause and effect relationships in nature. In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way. Just as it does for a professional scientist, the scientific method will help you to focus your science fair project question, construct a hypothesis, design, execute, and evaluate your experiment.
The Scientific Method The Scientific Method is a logical and rational order of steps by which scientists come to conclusions about the world around them. The Scientific Method helps to organize thoughts and procedures so that scientists can be confident in the answers they find. Scientists use observations, hypotheses, and deductions to make these conclusions, just like you will use the Scientific Method in your science fair project. You will think through the various possibilities using the Scientific Method to eventually come to an answer to your original question.
The Scientific Method Problem / Question Observation / Research Formulate hypothesis Experiment Manipulated variable the variable that is deliberately changed (independent variable) Responding variable is variable that is observed ( aka dependent variable) Collect and analyze data Conclusion Communicate results
Problem / Question Ask a Question: The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where? And, in order for the scientific method to answer the question it must be about something that you can measure, preferably with a number.
Observation / Research Do Background Research: Rather than starting from scratch in putting together a plan for answering your question, you want to be a savvy scientist using library and Internet research to help you find the best way to do things and insure that you don't repeat mistakes from the past.
Formulate a Hypothesis Construct a Hypothesis: A hypothesis is an educated guess about how things work: If [I do this], then [this] will happen. You must state your hypothesis in a way that you can easily measure, and of course, your hypothesis should be constructed in a way to help you answer your original question. Your hypothesis should be something that you can actually test, what's called a testable hypothesis. In other words, you need to be able to measure both "what you do" and "what will happen."
Experiment Test Your Hypothesis by Doing an Experiment: Your experiment tests whether your hypothesis is supported or not. It is important for your experiment to be a fair test. You conduct a fair test by making sure that you change only one factor at a time while keeping all other conditions the same. You should also repeat your experiments several times to make sure that the first results weren't just an accident.
Collect and Analyze Data Analyze Your Data: Once your experiment is complete, you collect your measurements and analyze them to see if they support your hypothesis or not. Scientists often find that their hypothesis was not supported, and in such cases they will construct a new hypothesis based on the information they learned during their experiment. This starts the entire process of the scientific method over again. Even if they find that their hypothesis was supported, they may want to test it again in a new way. Review your data. Try to look at the results of your experiment with a critical eye. Ask yourself these questions: Is it complete, or did you forget something? Do you need to collect more data? Did you make any mistakes? Calculate an average for the different trials of your experiment, if appropriate. Make sure to clearly label all tables and graphs. And, include the units of measurement (volts, grams, etc.). Place your independent variable on the x-axis of your graph and the dependent variable on the y-axis.
Conclusion Draw a Conclusion: Your conclusions summarize how your results support or contradict your original hypothesis: Summarize your experiment results in a few sentences and use this summary to support your conclusion. Include key facts from your background research to help explain your results as needed. State whether your results support or contradict your hypothesis. (Engineering & programming projects should state whether they met their design criteria.) If appropriate, state the relationship between the independent and dependent variable. Summarize and evaluate your experimental procedure, making comments about its success and effectiveness. Suggest changes in the experimental procedure (or design) and/or possibilities for further study.
Communicate the Results Communicate Your Results: To complete your science fair project you will communicate your results to others in a final report and/or a display board. Professional scientists do almost exactly the same thing by publishing their final report in a scientific journal or by presenting their results on a poster at a scientific meeting. In a science fair, judges are interested in your findings regardless of whether or not they support your original hypothesis.
The Scientific Method in Action Suppose you observed that a cricket outside your window seems to be chirping every night, but some nights it chirps faster than others. A friend of yours told you once that you can use the sound of a cricket chirp to tell the temperature. Curious, you decide to design an experiment. First you must create a hypothesis; here are some examples of possible hypotheses: The frequency of cricket chirps will change as the temperature changes. As the temperature decreases, a cricket will chirp fewer times. Either hypothesis will work, the important thing is that you can -test- the hypothesis by doing an experiment which will confirm or deny the statement. To set up the experiment, you go out to your yard and capture a few crickets. You bring them inside and place them in a container. But wait, if you have a bunch of crickets together, what if they chirp based on how many crickets there are nearby. The goal in designing an experiment is to eliminate all the variables except the one you are testing. This means all your cricket subject must be housed in the same environment (same lighting, same food, same water.. etc). Okay, so you get that set up and take the temperature of your room. Now you must wait for the crickets to start chirping. You count how many times the cricket chirps for a 5 minute period. Now you have to compare that number with the chirps that occur at different temperatures. You may use a heating pad, or ice or any other way to lower or raise their temperature. You would then take data for 5 minutes at the new temperature. In your experiment, the MANIPULATED VARIABLE is the thing you changed the temperature. The RESPONDING VARIABLE is what you are measuring that happens as a result of that change the number of chirps. The CONTROL GROUP isn t obvious in this case but you can consider your original (room temperature) data as your control, and the other temperatures your experimental data. After you have taken data, you can then draw a conclusion about whether your hypothesis is accepted (correct) or denied (incorrect).
Some useful scientific concepts Science using evidence to learn about the natural world; a body of knowledge Science begins with observations often taking data on what you see, hear or smell data the information gathered from observations quantitative data = numbers qualitative data = descriptive Inference a logical interpretation based on prior knowledge or experience (Ex. You see a window broken and a baseball on the floor next to the shattered glass. You can -infer- that a baseball broke your window) Hypothesis a proposed scientific explanation. This statement is testable and can be confirmed with experimentation or further observation. Prediction An if-then statement that shows what you expect to see as a result of an experiment or observation (Ex. If fertilizer makes a plant grow faster, then seedlings planted with fertilizer will be taller than the ones planted without fertilizer)