Scientific InvestigationsScientific Investigations

ObjectivesObjectivesReview the three types of investigationsReview the three types of investigations

Parts of an experimentParts of an experimentResearch question/PurposeHypothesisProcedure

Control groupExperimental groupIndependent variableDependent variable

ObservationsDataAnalysis/Conclusion

Research question/PurposeHypothesisProcedure

Control groupExperimental groupIndependent variableDependent variable

ObservationsDataAnalysis/Conclusion

Types of InvestigationsTypes of InvestigationsDescriptive

Comparative

Experimental

Descriptive

Comparative

Experimental

Descriptive InvestigationsDescriptive InvestigationsObservations made about an organism,

substance, reaction, or biological process

Collect quantitative and/or qualitative data

Observations made about an organism, substance, reaction, or biological process

Collect quantitative and/or qualitative data

Conducting a Descriptive LabConducting a Descriptive Lab Include the following parts of an

investigation:Research QuestionProcedure, Data, Analysis

Include the following parts of an investigation:Research QuestionProcedure, Data, Analysis

Examples of Descriptive LabsExamples of Descriptive Labs

How many mm3 per week does mold grow on a piece of bread?

What is the rate of growth of a new corn seedling?

How many mm3 per week does mold grow on a piece of bread?

What is the rate of growth of a new corn seedling?

Comparative LabsComparative Labs

Comparing the effect of a variable on two or more groups

Includes the all the parts of an experiment except the control group

Comparing the effect of a variable on two or more groups

Includes the all the parts of an experiment except the control group

Examples of Comparative LabsExamples of Comparative Labs

Does mold grow faster on bread slices kept in shoebox versus those kept in sunlight?

Do plants grow better under UV light or sunlight?

Does mold grow faster on bread slices kept in shoebox versus those kept in sunlight?

Do plants grow better under UV light or sunlight?

Experimental LabsExperimental LabsDetermines how a variable affects a

groupIncludes all parts of an experiment

Determines how a variable affects a group

Includes all parts of an experiment

Examples of Experimental LabsExamples of Experimental LabsHow does adding water to the bread

affect the rate of mold growth?

Does adding eggshells to the soil increase the rate of growth in tomato plants?

How does adding water to the bread affect the rate of mold growth?

Does adding eggshells to the soil increase the rate of growth in tomato plants?

Tenets of NOSTenets of NOS

•Tentative•Empirical•Subjective•Creative•Socially & Culturally Embedded•Observations & Inferences•Theories & Laws

•Tentative•Empirical•Subjective•Creative•Socially & Culturally Embedded•Observations & Inferences•Theories & Laws

TentativeTentative

Scientific knowledge changes in two ways; it grows as new knowledge is discovered and improves as old knowledge is revised corrected.

While scientific knowledge is tentative, there is also much reliability in scientific knowledge because of its empirical basis.

Ray Drenner - Hg Toxicity in Aquatic Systems

EmpiricalEmpirical

Scientific knowledge is based on observations of the natural world.

Although all scientific knowledge is based upon empirical evidence, much scientific knowledge (inferences & theories) lacks hard data directly accessible to the senses.

Archaeopteryx

Pangaea

SubjectivitySubjectivity

Scientists’ theoretical commitments and expectations influence their work.

Scientists’ observations acquire meaning in reference to questions or problems.

These questions or problems, in turn, are derived from certain theoretical perspectives (theory-laden).

H. Pylori

Drs. Barry Marshall & Robin Warren

CreativeCreative

Scientific knowledge involves human imagination and creativity.

Science involves the invention of explanations and this requires a great deal of creativity by scientists.

Dr. Bonnie Bassler

Social and CulturalSocial and Cultural

Science is practiced in the context of a larger culture and scientists are the product of that culture.

Science is affected by the various elements of the culture in which it is embedded.

These elements include social fabric, power structures, politics, socioeconomic factors, philosophy, and religion.

Stem Cell Research & HPV Vaccine

Observations and InferencesObservations and Inferences

Observations are descriptive statements about natural phenomena that are “directly” accessible to the senses.

By contrast, inferences are statements about phenomena that are not “directly” accessible to the senses.

Charles Darwin

And “his” finches

Theories and LawsTheories and LawsTheories and laws are different kinds of knowledge; one can not develop or be transformed into the other.

Laws are statements or descriptions of the relationships among observable phenomena (the “what”).

Theories, by contrast, are inferred explanations for observable phenomena (the “how”).