Yesterday, we asked “are all Yesterday, we asked “are all chemicals bad?”chemicals bad?”

No, but some can be dangerousNo, but some can be dangerous Chemicals are everywhereChemicals are everywhere

Which brings us to…Which brings us to…

What is What is ChemistryChemistry?? the study of matter and the changes the study of matter and the changes

that it undergoes.that it undergoes.

What is What is MatterMatter?? anything that has mass and takes up anything that has mass and takes up

space space

What is What is MassMass?? a measurement of the amount of a measurement of the amount of

matter in an object matter in an object

Mass verses WeightMass verses Weight

They are related, but what’s the They are related, but what’s the difference?difference?

MassMass is universal, is universal, weightweight depends on depends on gravitygravity

WeightWeight = = massmass times the gravitational pull times the gravitational pull

Branches of ChemistryBranches of Chemistry

OrganicOrganic InorganicInorganic AnalyticalAnalytical PhysicalPhysical BiochemicalBiochemical

OrganicOrganic

Area of EmphasisArea of Emphasis Most Most carboncarbon-containing chemicals-containing chemicals

Examples:Examples: PharmaceuticalsPharmaceuticals PlasticsPlastics

InorganicInorganic Area of EmphasisArea of Emphasis

In general, matter that does In general, matter that does notnot contain carboncontain carbon

Examples:Examples: MineralsMinerals MetalsMetals and and nonmetals nonmetals Semi-conductorsSemi-conductors

AnalyticalAnalytical

Area of EmphasisArea of Emphasis ComponentsComponents and and compositioncomposition of of

substancessubstances

Examples:Examples: Food NutrientsFood Nutrients Quality ControlQuality Control

PhysicalPhysical

Area of EmphasisArea of Emphasis The The behaviorbehavior and and changeschanges of of

matter and the related matter and the related energyenergy changeschanges

Examples:Examples: Reaction Reaction RatesRates Reaction Reaction MechanismsMechanisms

BiochemicalBiochemical

Area of EmphasisArea of Emphasis MatterMatter and and processesprocesses of living of living

organismsorganisms

Examples:Examples: MetabolismMetabolism FermentationFermentation

Next, the Scientific Next, the Scientific MethodMethod

Why do we have the Why do we have the scientific method?scientific method?

Gives us Gives us logicallogical steps to follow to steps to follow to assist us in answering a assist us in answering a questionquestion..

What are the “steps”?What are the “steps”?

Develop a Develop a questionquestion Conduct background Conduct background researchresearch Form a Form a hypothesishypothesis Test with an Test with an experimentexperiment Make Make observationsobservations and collect and collect datadata Analyze the Analyze the resultsresults Draw Draw conclusionsconclusions ReportReport results and test again results and test again

Parts of an experimentParts of an experiment

IndependentIndependent Variable Variable

PPart of the experiment that the scientist changes

What is being tested There is only one independent variable at

a time.

What I change

DependentDependent Variable Variable

PPart of the experiment that changes because of the

independent variable

ControlControl

PPart of the experiment that does not receive the independent

variable

ConstantsConstants

PPart of the experiment that remain the same for every part of the

experiment

Types of DataTypes of Data

QuantitativeQuantitative Data that is Data that is numericalnumerical in nature in nature

QualitativeQualitative Data that is Data that is descriptivedescriptive in nature in nature

An example experimentAn example experiment A person wants to test whether music can A person wants to test whether music can

help make plants grow. The person plants help make plants grow. The person plants several seeds from the same batch into several seeds from the same batch into identical flower pots with identical potting identical flower pots with identical potting soil, watering schedule and light supply. soil, watering schedule and light supply. One flower pot is isolated from the sound One flower pot is isolated from the sound supply, while the other pots are subjected supply, while the other pots are subjected to various types of music. After 1 month, to various types of music. After 1 month, the “healthiness” of each plant is the “healthiness” of each plant is measured.measured.