Mrs. Johnson | Blair Oaks Middle School Scientific Methods Mrs. Johnson | Blair Oaks Middle School

Definition The scientific method is a set of procedures that scientists follow in order to gain knowledge about the world by observing and performing experiments.

Video: Scientific Method

Theory versus Law A THEORY is an explanation of why something happens.  It comes from many observations and experiments.  It can be changed with new data. Example:  Theory of Evolution A LAW tells you what happens, like a rule of nature.   Examples:  Law of Gravity, Law of Thermodynamics

Six key steps that characterize the scientific method STEP 1: PROBLEM. This is the part where a scientist proposes the problem that he or she wants to solve. STEP 2: HYPOTHESIS. A well-conceived question usually leads to a hypothesis, a potential answer to the question at hand. Sometimes, hypotheses look more like predictions. The scientist predicts what the outcome will be when he or she tests the hypothesis.

Six key steps that characterize the scientific method STEP 3: EXPERIMENT: The scientist's test is also called the experiment. Experiments are ordered investigations that are intended to prove or disprove a hypothesis. Important data comes from performing an experiment.

Six key steps that characterize the scientific method STEP 4: OBSERVATIONS: The scientist has to make observations of the results from the experiment. An observation is a statement of knowledge gained through the senses or through the use of scientific equipment. STEP 5: ANALYSIS: Once the results are in, the scientist must begin the analysis. Data analysis involves comparing the results of the experiment to the prediction posed by the hypothesis.

Six key steps that characterize the scientific method STEP 6: CONCLUSION: Based on the observations he or she made, the scientist has to determine whether the hypothesis was correct. He or she then sums up his or her findings with a conclusion. Determine if hypothesis is supported or rejected. If hypothesis is not supported - modify hypothesis If hypothesis is supported - repeat experiment

Variables Controlled variables These are kept the same throughout your experiments Independent variable The one variable you purposely change and test Dependent variable The measure of change observed because of independent variable Decide how you will measure the change

Variables If you want to test the affect of fertilizer, you would add fertilizer to a plant (independent variable) and measure how the plant grows (dependent variable). You will also have a plant that receives no fertilizer (control).             Think:   The Independent variable is the thing that I changed

Variables A question or problem might look like this...... How does _________________ effect  ________________?                  (independent variable)          (dependent variable)

Pick A Problem/Question and Design an Experiment  Does the color red make lizards more aggressive? 2.  Will fish grow larger if placed in a larger tank? 3.  Does aspirin keep cut flowers fresh longer?