The Scientific Method

What is it? It is a way to organize thoughts and questions in a rational way to form conclusions about the world we live in

Two ways of thinking Inductive Reasoning- Uses separate specific observations to arrive at general principles A combination of these observations suggest a general conclusion A biologist examined and found separately that a tuna, sailfish and short-fin mako shark all have gills. Then they identify that all these are fish then… Through induction process, All Fish Had Gills.

Deductive Reasoning-Reasoning from general principles to specific conclusions Say a scientist made the inductive statement that all marine animals have gills then if whales are marine animals, then whales must have gills.

Make Observations and Ask Questions Why do sharks have so many teeth, because they are angry?

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Based on your observations, note any questions you have Why do their teeth have different shapes? Do the different shapes influence the composition in different species?

Do your background research! Look for primary research that is rlevant and based on your interest of study. Research journals and articles. Ebsco and Google scholar are great Wikipedia is not a research tool but may be useful to give yourself general information

Develop a Hypothesis Based on the question(s) you make after your observations, you must make an educated guess as to what you think the answer is to that particular question. This is called a HYPOTHESIS One important note – hypotheses must be testable. If there is a different shaped tooth then there will be a different compressive strength

Testing the hypothesis (Experiment) You can only test ONE factor at a time in any experiment. This allows you to be confident that the manipulation of that factor is responsible for the results of the experiment. Must be repeatable

Hypothesis Alternative Hypothesis If…..then statement If the shark teeth are different shapes then there will be a difference between compression strengths. Null Hypothesis-There will be no significant differences between the species shark teeth shape and compression strength

Components of an Experiment Independent variable: Manipulated variable (what the experimenter changes) Dependent variable: Responding variable (one that is measured/ quantified as a result) Constant: variables that are the same between ALL groups in an experiment Control group: group that is not manipulated and that the results are compared against (When appropriate) Experimental group: group where the variable is manipulated Trials/Sample Size: It is always best to run a large number of trials in an experiment as well as test a large sample size to get the best results.

Data Quantitative Numerical data Qualitative Descriptive data

Analyzing Data Data is often collected in charts and tables and then visually represented in graphs. Used to show information that changes over time or between related variables Used to group information and compare the groups

Circle graphs-Used to show how a part relates to the whole (percentages)

So what now….. After analyzing your data and graphs, you must make conclusions about your hypothesis based on your experiment. Your hypothesis will be either - IF SO… Re-run the experiment to see if you get the same results so that you can more accurately state that your hypothesis is correct. IF SO… Do more observations and come up with a new hypothesis to test. Experiment again. Not necessarily a bad thing, why?

Scientific Theory vs Law Scientific Theory-An explanation if things or events based on Knowledge gained from many observations and investigations. Just because the hypothesis has data supporting the theory does not make it unchangeable Theory of Evolution by natural selection

Scientific Law Scientific Law-is a statement about what happens in nature and seems to be true all the time Laws tell you what will happen under certain condition but not why or how it happened Newton’s Law of Gravity-states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Primary research article Abstract- Summary of all sections of the research paper Allows scientists to get an idea of the paper Introduction-Gives relevant background information on the subject and states the hypothesis Materials and Methods- Describes the experiment to allow for other scientist to replicate the experiment if needed. Must be thorough and descriptive

Results This section only presents the data that was recovered and describes them in graphs or tables It does not describe the trends of the data or any findings Conclusion- Describes any trends or findings during the experiment and identifies whether their hypothesis was supported Literature Cited- Lists all of the primary research that was cited during the paper This is very important!

Hand out time! Read the primary research article. Find the hypothesis and explain the conclusion of the paper