Chapter 1: Chemistry Chapter 1: Chemistry & You& You

Criteria of ScienceCriteria of ScienceConsistentConsistentObservable Observable Natural Natural PredictablePredictableTestableTestableTentativeTentative

Is it Science?Is it Science? Non-scienceNon-science – –

movie ratings, food movie ratings, food preferences preferences

PseudosciencePseudoscience – – phrenology, phrenology, homeopathyhomeopathy

Emerging science Emerging science – nanochemistry– nanochemistry

ChemistryChemistry The study of The study of

chemistry chemistry investigates all investigates all substances and substances and the changes they the changes they can go through.can go through.

submicroscopic submicroscopic levellevel

ChemistryChemistry Has its roots in the Has its roots in the

pseudoscience of pseudoscience of AlchemyAlchemy

Separated mixtures Separated mixtures and purified and purified chemicalschemicals

Lavoisier and Boyle Lavoisier and Boyle helped change helped change alchemy into a real alchemy into a real science by science by introducing structure introducing structure and experimentation.and experimentation.

The Scientific Method The Scientific Method BeginsBegins

CuriosityCuriosity

Observation, Observation, question, or problemquestion, or problem

““Hmmmmmm” Let Hmmmmmm” Let me think about that.me think about that.

HypothesisHypothesis Scientific HypothesisScientific Hypothesis: : A testable A testable

statement about the natural world statement about the natural world e.g. Bubbles will last longer in cold e.g. Bubbles will last longer in cold temperatures than in warm.temperatures than in warm.

AA hypothesishypothesis must be testable, must be testable, and be able to be potentially proven and be able to be potentially proven right or wrong. right or wrong.

Scientific Method Cont.Scientific Method Cont. Experimental ProceduresExperimental Procedures – –

Steps to test our hypothesis. Steps to test our hypothesis. ResultsResults and and Analyze your Analyze your

resultsresults.. ConclusionConclusion - Revise your - Revise your

hypothesis and start over again.hypothesis and start over again.

Control & VariablesControl & Variables Variable - Variable - what you are testingwhat you are testing

– Independent Variable – Independent Variable – changed changed by the experimenter. by the experimenter.

– Dependant Variable –Dependant Variable –changes in changes in response to the Independent response to the Independent Variable.Variable.

Control - Control - standard for comparison.standard for comparison.

Scientific MethodScientific Method After results are reproducible, After results are reproducible,

scientific studies are published in scientific studies are published in journals.journals.

Scientists review and critique Scientists review and critique published work.published work.

Science is self correcting and Science is self correcting and tentative.tentative.

Scientific Theories and Scientific Theories and LawsLaws

TheoryTheory – well tested – well tested explanation that unifies a broad explanation that unifies a broad range of observations and range of observations and scientific results. (atomic scientific results. (atomic theory, cell theory)theory, cell theory)

Strong predictive abilities (Plate Strong predictive abilities (Plate tectonics). tectonics).

Scientific LawScientific Law:: Concise Concise statement that summarizes the statement that summarizes the results of many observationsresults of many observations

e.g., Dalton’s Law, Laws of e.g., Dalton’s Law, Laws of Thermodynamics, Law of Thermodynamics, Law of ConservationConservation

The Scientific MethodThe Scientific Method

Remember that it is crucial for the data to be analyzed and then adjust your theory accordingly.

ExperimentationExperimentation Remember that after experimentation, Remember that after experimentation,

the data must be analyzed.the data must be analyzed. At this point, one of three things can At this point, one of three things can

happen.happen.– The hypothesis or theory can be tossed out The hypothesis or theory can be tossed out

because the experimental data disproves it.because the experimental data disproves it.– The theory has to be adjusted through more The theory has to be adjusted through more

experimentation.experimentation.– The data gives enough information where The data gives enough information where

predictions can be made and we have a LAW.predictions can be made and we have a LAW.

SummarySummary The key is to know the steps of the The key is to know the steps of the

scientific method, especially the last scientific method, especially the last step where an idea; theory or step where an idea; theory or hypothesis, must be adjusted and hypothesis, must be adjusted and the experimentation begins again. the experimentation begins again. This loop can go on for centuries. This loop can go on for centuries. We see this in atomic theory and We see this in atomic theory and plate tectonics.plate tectonics.