Scientific Methodology

Science is… a way of knowing about the natural world. a process using observation and data to investigate and understand our universe.

Scientific Methodology based on observation and interpretation of physical evidence subject to strict, repeated testing and peer review

Observation vs. Inference

Observation use one or more of your senses Good observations are accurate (exact) and objective (unbiased) Observations are either qualitative (no #’s) or quantitative (uses #’s)

Tell if the following are accurate and objective Observation Tell if the following are accurate and objective 16 students were on-time to class, and five students were tardy Half the class was late The funniest people showed up first accurate & objective inaccurate subjective

Tell if the following are qualitative or quantitative: Observation Tell if the following are qualitative or quantitative: The door is blue There are three doors in the room The floor tiles are shiny The floor tiles are 12”x12” qualitative quantitative qualitative quantitative

Inference when you explain or interpret an observation should be reasonable (makes sense) some inferences are unreasonable (far-fetched)

inference, unreasonable EXAMPLES I see football players wearing uniforms, they must have a game today. they must like string cheese. observation inference, reasonable inference, unreasonable

The plant is growing in soil Observation or Inference? The plant is in a pot The plant is green The plant is growing in soil The plant has leaves The plant has roots The plant uses water observation inference

Self Check What two qualities make an observation scientific? Can you write a scientific observation about the classroom? How is an inference different from an observation?

Observations lead to Questions A scientific Question or Problem arises from our observations. Observation: My dog is shedding more than usual. What kinds of questions might you ask after this observation? http://www.free-clipart-pictures.net/dog_clipart.html

Hypothesis A hypothesis is an educated guess as to what you think the answer to your question might be. Good hypotheses are reasonable and evidence based.

Experiment Determine a Procedure to test whether hypothesis is correct. The outcome must be measureable (quantifiable).

Experiment When testing, it is important to perform a controlled experiment. Many experiments have an “experimental group” and a “control group”. The two groups are treated EXACTLY alike except for the ONE variable being tested. A student runs an experiment to see which fish food makes fish grow faster. What variables exist between the two groups? http://underwaterlife.blogetery.com/2010/09/21/tips-for-selecting-an-aquarium-store/

Experiment The control group is the baseline, or standard, against which you measure the effect of the introduced variable. The experimental group is the group into which you introduce one varying factor (variable). + + http://www.wpclipart.com/cartoon/people/caricature/Mad_scientist_caricature.png.html

Experiment For example, in an experiment to test the effects of a memory-enhancing drug, there would be a control group, consisting of normal, everyday people… … while the experimental group is given a pill that is intended to improve their memory. + +

Experiment Nearly all experiments have variables – or factors that can affect an experiment. There are three types: independent (manipulated) dependent (responding) controlled variables

Experiment Independent (manipulated) variable the thing that someone actively changes, What you are testing the “cause” Dependent (responding) variable the thing that changes as a result of the independent variable The thing you measure the “effect”

Experiment EXAMPLE In our memory-enhancing drug experiment… independent variable = (what we test) dependent variable =(what we measure) pill given to members of the experimental group memory of members in the experimental group

Experiment control variable = any factors that could have an affect on your experiment. In the memory experiment, what factors do you need to control, so we know the ONLY thing changing memory is the pill? The people need to be the same age, in case younger brains are better at memory People need to be around similar intelligence levels, it could affect the results of the memory test The test: both groups must be given the same test in order to compare.

Data DATA Data must be measurable and accurate! Asking the participants if they think their memory is better Not accurate, subjective Giving a test before and after, and comparing scores Accurate, objective

Analysis! ANALYSIS Examine the data from your experiment, looking for trends, patterns, or any other evidence that can lead to a reasonable conclusion

Analysis If the expected results are obtained, the hypothesis is supported (but not proven). If the expected results are NOT obtained, the hypothesis is null.

In the case of our memory-drug experiment: Analysis ANALYSIS In the case of our memory-drug experiment: We would look at our data and try to determine if the memory of the people in our experimental group was any better (or worse) than the memory of those in our control group +

Conclusion Restate your hypothesis State whether your prediction was confirmed Explain your results. When writing a conclusion for labs: Include discussion of errors Include Future Research ideas

Peer Review / Communicate Results Finally, results are shared so that other experts can replicate the experiment and look for flaws or problems.