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The Nature of Science, TMS, and Validity in Science

The Nature of Science

As we know from discussions and examples in class, the "scientific method" is not just "6 steps in order" with a beginning in an end.  In reality, the nature of science is more circular, with repetition and cycling back.  What makes science science is not a step-by-step process that we memorize, but the "habits of mind" that all scientists practice: classifying, evaluating, analyz­ing and synthesizing, and inferring.   There is organization in scientific endeavors, and it is very important to undersand the difference between observations and interpretations, but creativity also plays a part.  The "stereotypical scientist" image in many people's minds is only a fraction of what real scientists "look like."  In fact, much science that happens doesn't happen in a lab with safety goggles and strange chemicals.  Scientists are everywhere!

All that being said, real science might take on many forms.  Sometimes it will be experiments with chemicals or plants, or models and planned experiments.  Other times, observation in a natural setting will be the forefront, with data collection and analysis being the focus.  *

For science is that is based on experimentation, it is important to meet certain standards to make sure the experiment, and its subsequent results, are valid.  The "TMS" rule is a helpful way to determine whether a planned experiment will in fact be "scientific."

 

TMS

For science is that is based on structured experimentation, it is important to meet certain standards to make sure the experiment, and its subsequent results, are valid.  The "TMS" rule is a helpful way to determine whether a planned experiment will in fact be "scientific."

 

Test and Control
  • At least two groups must be COMPARED.  This is usually a test group and an control group, but more complex experiments may have a control and several test groups.
  • Groups or subjects or items which are being compared with one another must differ in only one way.
  • Traditionally, the "control" group has nothing done to it.  In some chemistry experiments, distilled water is the control.  When testing new drugs, test subjects in the control group may receive a "sugar pill" or placebo instead of the actual drug.

 

Multiple Trials

  • Science must be REPLICATED and REPLICABLE.  This can be accomplished through replication or through multiple trials.
  • Replication means that the same exact comparison (the same experiment) is repeated.  [For example, a physics lab in Maine does the same experiement that a physics lab in France has done.] 
  • Multiple trials means that, within one experiment, there are duplicate trials.  Essentially, you are doing the same experiment multiple times at the same time.  [For example, when we did the Yeast Lab in class, we had 7 samples of Bag A, 7 samples of Bag B and 7 samples of Bag C beign tested in the same class.]

 

Same conditions

  • For an experiment to be valid, it must be "FAIR."  This means that variables must be limited to one.
  • Every feature of your test group and your control group (or the two groups you are comparing) must be identical, except one.  The one difference is the independent variable.  
  • Rationale:  If more than one thing is different between the two groups you are comparing, you will not be able to say with certainty what caused a difference in your results (if there is a difference in results between the groups).  By limiting the initial input differences to a single factor, any change in outcome can be directly linked to that single factor.  Your conclusion will be validated.
  • Phrases that mean the same thing as "same conditions" include:  limiting variables, keeping conditions constant, controlling variables.
  • Remember: "Everything, everything, everything stays the same except the independent variable."  *Note: this refers to experimental design, not to the results of an experiment.

 

 

 

 

 

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