biology

BiologyBiology

Study of lifeStudy of life

Goals of ScienceGoals of Science

Investigate and understand natureInvestigate and understand nature Explain events in natureExplain events in nature Use explanations to make predictionsUse explanations to make predictions

SCIENCESCIENCE

Organized way of using evidence to learn about the natural world.Organized way of using evidence to learn about the natural world.

Scientist assume that the universe is a system in which basic Scientist assume that the universe is a system in which basic natural laws apply. natural laws apply.

Qualities of a scientistQualities of a scientist

Open-Mindedness – willing to accept Open-Mindedness – willing to accept different ideas that they may not agree with.different ideas that they may not agree with.

Skepticism – Question existing ideas and Skepticism – Question existing ideas and hypothesis, and they refuse to accept hypothesis, and they refuse to accept explanations without evidence.explanations without evidence.

CuriosityCuriosity CreativityCreativity

Lesson OverviewLesson Overview Science in ContextScience in Context

Curiosity A curious researcher, for example, may look at a salt marsh and immediately ask, “What’s that plant? Why is it growing here?”

Often, results from previous studies also spark curiosity and lead to new questions.


Skepticism Good scientists are skeptics, which means that they question existing ideas and hypotheses, and they refuse to accept explanations without evidence.

Scientists who disagree with hypotheses design experiments to test them.

Supporters of hypotheses also undertake rigorous testing of their ideas to confirm them and to address any valid questions raised.


Open-Mindedness Scientists must remain open-minded, meaning that they are willing to accept different ideas that may not agree with their hypothesis.


Creativity Researchers need to think creatively to design experiments that yield accurate data.

Biologist StudyBiologist Study

Study Diversity of Life Study Diversity of Life ((ex. Jane Goodall studies “ ex. Jane Goodall studies “ How chimpanzees behave in wild”)How chimpanzees behave in wild”)

Research DiseaseResearch Disease– What causes disease?What causes disease?– How does body fight disease?How does body fight disease?– Develop vaccinesDevelop vaccines– New medicinesNew medicines

Develop technologiesDevelop technologies– ““bionic” handbionic” hand– Store and transport blood plasma for transfusions-Store and transport blood plasma for transfusions-

saved countless soldiers life WWII.saved countless soldiers life WWII. Improve AgricultureImprove Agriculture Preserve the environmentPreserve the environment

BiologyBiologyChapter 1

Life

Characteristics Of Living ThingsCharacteristics Of Living Things

LIVING THINGS…..LIVING THINGS….. made of cellsmade of cells based on universal genetic codebased on universal genetic code reproducereproduce grow and developgrow and develop adjust to their surroundings--respondadjust to their surroundings--respond adapt and evolveadapt and evolve obtain and use energy-metabolismobtain and use energy-metabolism maintain stable internal environmentmaintain stable internal environment

Living Things Are OrganizedLiving Things Are Organized

Composed of one or more cells Composed of one or more cells that are based genetic code.that are based genetic code.

Organization: an arrangement of Organization: an arrangement of parts (cells) for the performance parts (cells) for the performance of the functions necessary to lifeof the functions necessary to life

Organisms Number of CellsOrganisms Number of Cells

MulticellularMulticellular – Organisms made of many – Organisms made of many cells (cells specialized to perform different cells (cells specialized to perform different functions)functions)

(ex. monkey and trees)(ex. monkey and trees)

UnicellularUnicellular – One cells organisms – One cells organisms ( ex. Amoeba)( ex. Amoeba)

Types of CellsTypes of CellsProkaryotesProkaryotes – an organism, characterized by – an organism, characterized by the absence of a nuclear membrane and by the absence of a nuclear membrane and by DNA that is not organized into chromosomes. DNA that is not organized into chromosomes. (ex. bacteria)(ex. bacteria)

EukaryotesEukaryotes – an organism composed of one – an organism composed of one or more cells containing visibly evident nuclei or more cells containing visibly evident nuclei and organelles (ex. plants and animals)and organelles (ex. plants and animals)

Living Things Make More Living Things Make More Living ThingsLiving Things

Reproduction: Production of an offspring by Reproduction: Production of an offspring by an organism.an organism.

Species: Organisms that can Species: Organisms that can interbreedinterbreed and and produce produce fertilefertile offspring in nature. offspring in nature.

(Reproduction is not essential for an individual (Reproduction is not essential for an individual organism, but for continuation of a species)organism, but for continuation of a species)

Types of ReproductionTypes of Reproduction

•Sexual – Requires two parents and offspring are not identical•Asexual – Requires one parent and offspring identical

Living Things Change Living Things Change During Their LivesDuring Their Lives

single cell grows and takes on the single cell grows and takes on the characteristics of its species.characteristics of its species.

GrowthGrowth: Increase in the amount of material : Increase in the amount of material and formation of new structures in an and formation of new structures in an

organism.organism.DevelopmentDevelopment: All of the changes that take : All of the changes that take

place during the life of an organism.place during the life of an organism.

Living Things Adjust to Living Things Adjust to Their SurroundingsTheir Surroundings

EnvironmentEnvironment: Living and nonliving surroundings to which : Living and nonliving surroundings to which an organism must constantly adjustan organism must constantly adjust (air, water, weather, temperature, other organisms, other factors)(air, water, weather, temperature, other organisms, other factors)

StimulusStimulus: Any condition in the environment that requires : Any condition in the environment that requires an organism to adjustan organism to adjust

ResponseResponse: : A reaction to stimulusA reaction to stimulus

HomeostasisHomeostasis

Organism’s regulation of its Organism’s regulation of its internal environment to maintain internal environment to maintain conditions suitable for survival.conditions suitable for survival.

HomeostasisHomeostasis

Obtain and use materials Obtain and use materials and energyand energy

•Used to grow, develop and reproduceUsed to grow, develop and reproduce•Metabolism-chemical reactions through Metabolism-chemical reactions through which an organism builds up or breaks which an organism builds up or breaks down materials.down materials.

Living Things Adapt and Living Things Adapt and EvolveEvolve

AdaptationAdaptation: Evolution of a structure, behavior, or : Evolution of a structure, behavior, or internal process that enables an organism to internal process that enables an organism to

respond to stimuli and better survive in an respond to stimuli and better survive in an environment. environment.

Evolution: Evolution: Gradual accumulation of adaptations Gradual accumulation of adaptations over time.over time.

DO NOW:DO NOW:

Have you or a close relative ever Have you or a close relative ever collected a particular item? How collected a particular item? How

did you/they organize their did you/they organize their collection?collection?

ClassificationClassification

Grouping of ideas, things, etc. on Grouping of ideas, things, etc. on the basis of similaritiesthe basis of similarities

Ex. Classifying trees as plants, or Ex. Classifying trees as plants, or classifying horses as animalsclassifying horses as animals

ClassificationClassification

Taxonomy-Branch of biology that deals with Taxonomy-Branch of biology that deals with the classification of living things.the classification of living things.

Taxonomist-A person who works at or Taxonomist-A person who works at or studies taxonomystudies taxonomy

What is a Classification What is a Classification System?System?

A classification system is a way to identify A classification system is a way to identify an organism and place it into the correct an organism and place it into the correct

group of related organisms (similar group of related organisms (similar characteristics)characteristics)

Classification HistoryClassification History Aristotle (2000 years ago)Aristotle (2000 years ago)

– 11stst attempt to classify attempt to classify– All organisms two groups-KingdomsAll organisms two groups-Kingdoms

• AnimaliaAnimalia• PlantaePlantae

Ernest Haeckel (1866)Ernest Haeckel (1866)– Proposed 3Proposed 3rdrd Kingdom-Protista Kingdom-Protista

• All organisms that did not fall under plantae or animaliaAll organisms that did not fall under plantae or animalia– Eg. Euglena-had characteristics of both plants and animalsEg. Euglena-had characteristics of both plants and animals

As scientist learned more, more Kingdoms As scientist learned more, more Kingdoms addedadded

Classification History cont. Classification History cont.

Kingdom Fungi was proposedKingdom Fungi was proposed– Organisms from this kingdom were originally Organisms from this kingdom were originally

classified as plants, but fungi are not classified as plants, but fungi are not photosynthetic and are heterotrophic, so they photosynthetic and are heterotrophic, so they became part of separate Kingdom.became part of separate Kingdom.

Robert Whittaker(1969)Robert Whittaker(1969)– Proposed 5 Kingdom Classification based upon Proposed 5 Kingdom Classification based upon

the following:the following:• Number of cellsNumber of cells• Presence or absence of a nucleusPresence or absence of a nucleus• Mode of nutritionMode of nutrition

Classification TodayClassification Today

6 Kingdom Classification 6 Kingdom Classification 1.1. Kingdom AnimialiaKingdom Animialia2.2. Kingdom PlantaeKingdom Plantae3.3. Kingdom FungiKingdom Fungi4.4. Kingdom ProtistaKingdom Protista5.5. Kingdom Bacteria or Monera or EubacteriaKingdom Bacteria or Monera or Eubacteria6.6. Kingdom Archaea or ArchaeabacteriaKingdom Archaea or Archaeabacteria

6 Kingdoms-3 Domains of Life6 Kingdoms-3 Domains of Life

Domain Bacteria-Kingdom Bacteria or MoneraDomain Bacteria-Kingdom Bacteria or Monera Domain Archaea-Kingdom Archaebacteria or Domain Archaea-Kingdom Archaebacteria or

ArchaeaArchaea Domain Eukarya (derives from Eukaryotic-Domain Eukarya (derives from Eukaryotic-

Nucleus)-Kindgoms Animalia, Plantae, Nucleus)-Kindgoms Animalia, Plantae, Protista and FungiProtista and Fungi

Note- Domains are the largest group of Note- Domains are the largest group of classification; Kingdoms are just below classification; Kingdoms are just below domainsdomains

Kingdom AnimaliaKingdom Animalia

MulticellularMulticellular Contain specialized tissues and cellsContain specialized tissues and cells Heterotrophic (obtain food from outside)Heterotrophic (obtain food from outside) MotileMotile EukaryoticEukaryotic Reproduce sexually (higher animals) and Reproduce sexually (higher animals) and

asexually (lower organisms)asexually (lower organisms) 2 groups2 groups

– Invertebrates- without backboneInvertebrates- without backbone– Vertebrates- with backboneVertebrates- with backbone

Kingdom FungiKingdom Fungi Unicellular or multicellularUnicellular or multicellular Heterotrophic (obtain food by absorption)Heterotrophic (obtain food by absorption) Non motileNon motile Reproduction both sexual and asexualReproduction both sexual and asexual Saprophytic (nourishment from dead or decaying Saprophytic (nourishment from dead or decaying

organisms) or parasitic (feed on others)organisms) or parasitic (feed on others) Made up of Hyphae/mycelium (mass of hyphae)Made up of Hyphae/mycelium (mass of hyphae) EukaryoticEukaryotic Cell walls of chitin (skeletal like material)Cell walls of chitin (skeletal like material) Ex. Unicellular=yeast; multicellular=mushroomEx. Unicellular=yeast; multicellular=mushroom

Kingdom ProtistaKingdom Protista

Unicellular Unicellular Colonial (living in groups) or multicellularColonial (living in groups) or multicellular Autotrophic (euglena) and heterotrophic (by Autotrophic (euglena) and heterotrophic (by

ingestion)ingestion) Some are motileSome are motile EukaryoticEukaryotic Ex paramecium, euglena, volvox and Ex paramecium, euglena, volvox and

amoebaamoeba

Kingdom Bacteria or MoneraKingdom Bacteria or Monera UnicellularUnicellular AsexualAsexual Prokaryotic (no true nucleus)Prokaryotic (no true nucleus) Some Saprophytic or parasitic Some Saprophytic or parasitic Autotrophic or heterotrophicAutotrophic or heterotrophic MicroscopicMicroscopic Non-motile and motileNon-motile and motile

– Motile by means of flagellumMotile by means of flagellum 3 shapes3 shapes

– Round-Coccus (cocci-plural)Round-Coccus (cocci-plural)– Spiral- Spirillus (spirilli-plural)Spiral- Spirillus (spirilli-plural)– Rod- Bacillus (bacilli-plural) Rod- Bacillus (bacilli-plural)

Kingdom PlantaeKingdom Plantae MulticellularMulticellular Contain specialized tissues and cellsContain specialized tissues and cells PhotosyntheticPhotosynthetic Autotrophic (make own food)Autotrophic (make own food) Non-Motile or sessile (non moving)Non-Motile or sessile (non moving) EukaryoticEukaryotic Reproduce sexually and asexuallyReproduce sexually and asexually Cell Walls made of Cellulose (carbohydrate)Cell Walls made of Cellulose (carbohydrate) Divided into 2 groups-Flowering and non-floweringDivided into 2 groups-Flowering and non-flowering

Kingdom Archaea or Kingdom Archaea or ArchaebacteriaArchaebacteria

Similar to bacteriaSimilar to bacteria Survive in extreme environments (volcanoes, Survive in extreme environments (volcanoes,

hot springs, ocean vents)hot springs, ocean vents) Biochemically and genetically different from Biochemically and genetically different from

bacteriabacteria Has same shapes as other bacteriaHas same shapes as other bacteria 3 types:3 types:

– Methanogens- Produce methaneMethanogens- Produce methane– Halophiles – “salt loving” bacteriaHalophiles – “salt loving” bacteria– Thermophiles – “heat loving” bactera.Thermophiles – “heat loving” bactera.

Modern TaxonomyModern Taxonomy

Taxonomy done today: Sorting Taxonomy done today: Sorting and grouping of organisms based and grouping of organisms based

upon similar characteristicsupon similar characteristics

CARL LINNAEUSCARL LINNAEUS

Modern Taxonomy is based upon his workModern Taxonomy is based upon his work

Carolus LinneausCarolus Linneaus Swedish Botanist (1701-1778)Swedish Botanist (1701-1778) The “Founder” of Modern TaxonomyThe “Founder” of Modern Taxonomy Based his groups on structural similaritiesBased his groups on structural similarities Provided following Taxons in hierarchy:Provided following Taxons in hierarchy:

– Kingdom (broadest)Kingdom (broadest)– PhylumPhylum– ClassClass– OrderOrder– FamilyFamily– GenusGenus– Species (most specific)Species (most specific)

Taxon-A group of similar organisms based upon similar Taxon-A group of similar organisms based upon similar characteristics (Ex. Kingdom=taxon)characteristics (Ex. Kingdom=taxon)

TaxonsTaxonsThe more taxons the more closely relatedThe more taxons the more closely related

Linneaus’ HierarchyLinneaus’ Hierarchy

Kingdom-contains a group of related phylaKingdom-contains a group of related phyla Phylum-contains a group of related classesPhylum-contains a group of related classes Class-contains a group of related ordersClass-contains a group of related orders Order-contains a group of related familiesOrder-contains a group of related families Family-contains a group of related genusesFamily-contains a group of related genuses Genus-contains a group of related species Genus-contains a group of related species

(reminder-species are a group of related (reminder-species are a group of related organisms that can interbreed and produce organisms that can interbreed and produce FERTILE offspring)FERTILE offspring)

Binomial NomenclatureBinomial NomenclatureSystem for providing a scientific name (Linneaus)System for providing a scientific name (Linneaus)

Made up of Genus and Species Made up of Genus and Species Genus name is ALWAYS capitalizedGenus name is ALWAYS capitalized Species name is never capitalizedSpecies name is never capitalized Both names are ItalicizedBoth names are Italicized Genus name can be abbreviatedGenus name can be abbreviated Example:Example:

– Canis lupisCanis lupis – Scientific name of the wolf – Scientific name of the wolf– D. melanogaster – D. melanogaster – Scientific name of Drosophilia Scientific name of Drosophilia

flyfly

Dichotomous KeyDichotomous KeyAn identification key used by scientists to name An identification key used by scientists to name

and group organisms (classify)and group organisms (classify)

A dichotomous key is composed of a series A dichotomous key is composed of a series of of paired statementspaired statements (called a couplet) (called a couplet) containing opposing choices.containing opposing choices.– Ex. 1a. Organism has wings………….…..go to 2Ex. 1a. Organism has wings………….…..go to 2 1b. Organism does NOT have wings..go to 31b. Organism does NOT have wings..go to 3

Note: A dichotomous key SHOULD move from the Note: A dichotomous key SHOULD move from the general to the specific.general to the specific.

Common Names versus Common Names versus Scientific NameScientific Name

Common Name: Name commonly used for Common Name: Name commonly used for an organism. Ex. Dogan organism. Ex. Dog

Common names are NOT preciseCommon names are NOT precise– Ex. The word cat can describe many kinds of Ex. The word cat can describe many kinds of

cats not just the domestic cat.cats not just the domestic cat. Common names can give misleading Common names can give misleading

informationinformation– Ex. Using the name fish for an organism such as Ex. Using the name fish for an organism such as

a starfish is not accurate.a starfish is not accurate.• Starfish are not fish!!!!Starfish are not fish!!!!

Modern Classification Modern Classification TechniquesTechniques

Evidence from the Fossil Record (Radioactive Dating)Evidence from the Fossil Record (Radioactive Dating) Evidence from Anatomy (Comparative Structural Evidence from Anatomy (Comparative Structural

Anatomy)Anatomy) Evidence from Embryonic Development (Comparative Evidence from Embryonic Development (Comparative

Embryology)Embryology) Evidence from Biochemistry (Amino Acids)Evidence from Biochemistry (Amino Acids) Evidence from DNA (DNA sequencing)Evidence from DNA (DNA sequencing) Metabolic BehaviorMetabolic Behavior PhylogenyPhylogeny CladisticsCladistics

Evidence Fossil RecordsEvidence Fossil Records Use Carbon Dating (radioactive isotope CUse Carbon Dating (radioactive isotope C1414))

to find age or organisms up to 50,000 years to find age or organisms up to 50,000 years ago.ago.– Help to determine ancestorsHelp to determine ancestors– Ex. Archaeopteryx is a believed to be an Ex. Archaeopteryx is a believed to be an

ancestor or today’s birds ancestor or today’s birds

Evidence from Anatomy Evidence from Anatomy (comparative structural anatomy)(comparative structural anatomy)

Structural anatomy is comparison on bones Structural anatomy is comparison on bones to suggest common ancestor.to suggest common ancestor.

HomologousHomologous structures- structures of structures- structures of differing organisms that would indicate differing organisms that would indicate similar originsimilar origin

Ex. Human arm, bat wing, horse’s leg, whale Ex. Human arm, bat wing, horse’s leg, whale flipper-similar structures suggesting common flipper-similar structures suggesting common ancestor; may be relatedancestor; may be related

Embryonic Development Embryonic Development (comparative embryology)(comparative embryology)

Comparison of early embryos to determine Comparison of early embryos to determine common ancestorcommon ancestor

Ex. Embryos of tunicates have structures Ex. Embryos of tunicates have structures similar to tadpolessimilar to tadpoles

Biochemistry EvidenceBiochemistry Evidence Arrangement of Amino Acids (Building Block Arrangement of Amino Acids (Building Block

of Proteins); similar patterns or sequencesof Proteins); similar patterns or sequences Ex. Human blood and baboon blood have Ex. Human blood and baboon blood have

very close amino acid sequence; therefore, very close amino acid sequence; therefore, more closely related than humans to horses.more closely related than humans to horses.

DNA EvidenceDNA Evidence

DNA-Deoxyribonucleic Acid (molecule that DNA-Deoxyribonucleic Acid (molecule that determines genetic makeup of an organism)determines genetic makeup of an organism)

Maps out genetic sequencing of an organismMaps out genetic sequencing of an organism Closer DNA sequence; more closely related.Closer DNA sequence; more closely related.

Evidence from Metabolic Evidence from Metabolic BehaviorBehavior

Ability to digest certain substances or Ability to digest certain substances or organisms is a producer, consumer or organisms is a producer, consumer or decomposerdecomposer

PhylogenyPhylogeny

Evolutionary history of an organismEvolutionary history of an organism Trace history to classifyTrace history to classify Phylogenic Tree (similar to family tree) – A Phylogenic Tree (similar to family tree) – A

tree that shows the relationships among tree that shows the relationships among various organisms.various organisms.– Roots suggest common ancestorRoots suggest common ancestor– Branches suggest new species have evolved Branches suggest new species have evolved

from new features (derived characteristics)from new features (derived characteristics)

CladisticsCladistics

Classification based on phylogeny; based Classification based on phylogeny; based upon the idea that there is a upon the idea that there is a common common ancestorancestor and new species gain derived and new species gain derived characteristicscharacteristics

Cladogram-branching diagrams used to trace Cladogram-branching diagrams used to trace the evolutionary history of organisms and to the evolutionary history of organisms and to then classify them then classify them

CladogramsCladograms

Speciation Event-Separation of organisms Speciation Event-Separation of organisms into different groups or species.into different groups or species.

Internode-A common ancestor to any Internode-A common ancestor to any branches above it.branches above it.

Root-A common ancestor to all organisms Root-A common ancestor to all organisms above it.above it.

Sister Taxons- Organisms very closely Sister Taxons- Organisms very closely relatedrelated

Do Now: Suppose you want to test phone cover/skins to decide which is best for protecting your cell phone. What materials would you need? What procedure would you follow? How would you determine which cover best protected your phone?

http://www.youtube.com/watch?v=eA86dYxrg4Q&feature=youtube_gdata_player

A common misperception of A common misperception of science is that science defines science is that science defines

"truth." Science does not define "truth." Science does not define truth; rather, it defines a way of truth; rather, it defines a way of thought. It is a process in which thought. It is a process in which experiments are used to answer experiments are used to answer questions. This process is called questions. This process is called

the scientific method. the scientific method.

The Advantages of Method

Clarifies our thoughts Uses human potential

Ends aimless wandering Aids in transfer of learning

Guides us to new knowledge Trains for change and innovation

Helps ideas gather shape Is a repeatable procedure

Organizes our thoughts Encourages thinking

The Opposite of Method is Chance

Wasted time Quick fixes

Wrong analysis Wasted energy

Haphazard guesses Wandering aimlessly

No Solutions Mistakes and errors

Confusion Misdirection

Scientific MethodScientific Method

Chapter 1

Scientific Method: Scientific Method: Series of organized steps/procedures that scientist use to Series of organized steps/procedures that scientist use to

solve problems and answer questions.solve problems and answer questions.(A process for investigating nature)(A process for investigating nature)

Observing and Stating the ProblemObserving and Stating the Problem Collecting Data/Gathering InformationCollecting Data/Gathering Information Form a HypothesisForm a Hypothesis Perform an ExperimentPerform an Experiment Analyze DataAnalyze Data Draw Conclusions based on your hypothesis Draw Conclusions based on your hypothesis

and experiment.and experiment. Report ResultsReport Results

Observing /ObservationsObserving /Observations

Sees, hears, or in some way Sees, hears, or in some way notice something no one has notice something no one has

noticed before.noticed before.

If the facts don't fit the theory, change the facts. -- Albert Einstein

State the ProblemState the Problem

A scientist can’t begin to solve a A scientist can’t begin to solve a problem until it is clearly stated.problem until it is clearly stated.

For instance, when going to the For instance, when going to the doctor you tell the doctor what is doctor you tell the doctor what is

wrong. (e.g. you have a sore wrong. (e.g. you have a sore throat)throat)

In lab the Problem is always stated in the form of a question.

Gather InformationGather Information

After defining your problem you After defining your problem you need to gather informationneed to gather information

For instance, a doctor would ask For instance, a doctor would ask how long you have had a sore how long you have had a sore

throat, take your temperature, and throat, take your temperature, and examine your throat.examine your throat.

HypothesisHypothesisGreek: hypo-”under”, thesis-”placing”Greek: hypo-”under”, thesis-”placing”

A tentative explanation for a question or A tentative explanation for a question or problem that can be formally tested. problem that can be formally tested.

Source for hypothesis: Prior knowledge, Source for hypothesis: Prior knowledge, logical inferences, and informed, creative logical inferences, and informed, creative

imagination.imagination.

For instance, based on experience, the doctor For instance, based on experience, the doctor theorizes that you have strep throat which theorizes that you have strep throat which

can be tested in a laboratory.can be tested in a laboratory.

Perform an experimentPerform an experiment

A procedure/series of steps that A procedure/series of steps that test a hypothesis under controlled test a hypothesis under controlled

conditions.conditions.

Controlled Experiment and Controlled Experiment and VariableVariable

Chapter 1

Experiment ConsiderationsExperiment ConsiderationsUsing Tools-Beakers, test tubes, hot plates, petri dishes, thermometers, dissecting instruments, balances, rulers, microscopes, centrifuges, radiation detectors, etc.

Maintaining Safety

•Minimize hazards

•Know your safety symbols

•Your responsibility to protect yourself as well as your classmates.

Experimental ConsiderationsExperimental Considerations

Data

Information obtained from experiment

Quantitative: Numerical form (distance, height)

Qualitative: Verbal Form (descriptions, behaviors)

Sometimes referred to as experimental results.

Experiment FactorsExperiment Factors

Control group- group in which all conditions are kept the same (Standard used to compare with the outcome of a test)

Experimental group-Test Group; receives the variable

Controlled Experiments:Controlled Experiments:Only one condition/factor changesOnly one condition/factor changes Variable-The factor being tested in an experiment

Independent Variable (manipulated variable)-Condition in an experiment that is changed. The only variable that affects the outcome of the experiment. (temperature, nutrients, light, soil)

Dependent Variable (responding variable)-A condition that results from change. Depends on changes from independent variable. (height, color, etc)

Independent DependentIndependent Dependent Presence of bacteriaPresence of bacteria Soil nutrientsSoil nutrients VitaminsVitamins Play Wii Fit 30 m/dPlay Wii Fit 30 m/d petri dish with growth petri dish with growth

medium medium

Growth rateGrowth rate Plant heightPlant height Cholesterol LevelsCholesterol Levels WeightWeight Growth on dishGrowth on dish

Analyze DataAnalyze Data

Data collected from the Data collected from the experiment is analyzed.experiment is analyzed.

For your sore throat, a lab For your sore throat, a lab technician identifies the growth technician identifies the growth and records data in your chart.and records data in your chart.

Draw ConclusionDraw Conclusion

Data is used to draw conclusions.Data is used to draw conclusions.

A A conclusionconclusion is a logical answer is a logical answer to a question based on data and to a question based on data and observations of the test material.observations of the test material.

Does your data support or reject Does your data support or reject your original hypothesis?your original hypothesis?

If the data shows that your sore throat was caused by If the data shows that your sore throat was caused by another kind of bacterium, you don’t have strep throat another kind of bacterium, you don’t have strep throat and the original hypothesis is and the original hypothesis is rejectedrejected. The doctor . The doctor must now revise the hypothesis to include a different must now revise the hypothesis to include a different cause of sore throat.cause of sore throat.

If the hypothesis was If the hypothesis was supportedsupported a scientist will a scientist will sometimes perform additional experiments and sometimes perform additional experiments and gather more data to strengthen their conclusion.gather more data to strengthen their conclusion.

If the experiment supports the hypothesis that you If the experiment supports the hypothesis that you have strep throat, and the doctor feels the data is have strep throat, and the doctor feels the data is sufficient to be statistically valid they may skip further sufficient to be statistically valid they may skip further experimentation and proceed to reporting results.experimentation and proceed to reporting results.

Reporting ResultsReporting Results

The last step in solving a problem The last step in solving a problem scientifically is to do something scientifically is to do something with the results. This includes with the results. This includes sharing data and suggesting sharing data and suggesting

remedies.remedies.

Your doctor may prescribe an Your doctor may prescribe an antibiotic to kill the bacteria.antibiotic to kill the bacteria.

Share IdeasShare Ideas

Peer Review – Publishing peer-reviewed Peer Review – Publishing peer-reviewed articles in scientific journals allows articles in scientific journals allows researchers to share ideas and to test and researchers to share ideas and to test and evaluate each other’s work. evaluate each other’s work.

Conducting experimentsConducting experiments

• No experiment is a failureNo experiment is a failure

• The results of every experiment can be used The results of every experiment can be used to revise the hypothesis or plan tests of a to revise the hypothesis or plan tests of a different variable.different variable.

Chapter 1

Scientific TheoryScientific Theory

Hypothesis successfully passes many test Hypothesis successfully passes many test over a long period of time and proves over a long period of time and proves

useful in knitting together a large body of useful in knitting together a large body of scientific work, it takes on the status of scientific work, it takes on the status of

TheoryTheory..

TheoryTheory- A tested explanation of a broad - A tested explanation of a broad segment of basic natural phenomena.segment of basic natural phenomena.

e.g. Atomic Theorye.g. Atomic TheoryBe Valid: Be Valid: explain observationsexplain observations

be repeatablebe repeatable be predictablebe predictable

Scientific LawScientific LawA concise statement in words or a A concise statement in words or a mathematical equation, about a mathematical equation, about a

fundamental relationship or regularity of fundamental relationship or regularity of nature.nature.

e.g. During a chemical reaction, no e.g. During a chemical reaction, no detectable gain or loss of mass occurs.detectable gain or loss of mass occurs.

Does not explain behavior of nature, it just Does not explain behavior of nature, it just states the generalized experimental finding. states the generalized experimental finding.

Comparing Theories and LawsComparing Theories and Laws

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ActivityActivity

Create a chart that:Create a chart that: Defines scientific law, theory and Defines scientific law, theory and hypothesishypothesis Provide qualities/characteristics that Provide qualities/characteristics that distinguish each of them (how do I know distinguish each of them (how do I know it’s a law, theory or hypothesis)it’s a law, theory or hypothesis) Examples of eachExamples of each

ReasearchReasearch

ResearchResearch Quantitative—Controlled experiments Quantitative—Controlled experiments

that results in counts or that results in counts or measurements. measurements. – Numerical dataNumerical data– Graphs and tablesGraphs and tables

Descriptive researchDescriptive research

Observational data; Observational data; Written descriptions of Written descriptions of what scientist what scientist observes.observes.

Science and SocietyScience and Society

EthicsEthics

Moral principles and values held by Moral principles and values held by humanshumans

-social, ethical moral concerns -social, ethical moral concerns when planning an investigation.when planning an investigation.

TechnologyTechnology

Application of scientific researchApplication of scientific research

Making improvements in human life Making improvements in human life and world around usand world around usIncrease production of foodIncrease production of foodReduced manual laborReduced manual laborReduction of waste and environmental Reduction of waste and environmental pollution.pollution.

BiasBias

Particular preference or point a Particular preference or point a view that is personal, rather than view that is personal, rather than

scientificscientific

Metric SystemMetric System

A decimal system of weights and A decimal system of weights and measurements based on meter measurements based on meter

and kilogram.and kilogram.

SI UnitsSI Units

Brief Chronological History Brief Chronological History of the Metric Systemof the Metric System

1670—Gabriel Moulton, a French mathematician, proposes a measurement system based on a physical quantity of nature and not on human anatomy.

1790—The French Academy of Science recommends the adoption of a system with a unit of length equal to one ten-millionth of the distance on a meridian between Earth’s North Pole and equator.

1870—A French conference is set up to work out standards for a unified metric system.

History continued…History continued…1875—The treaty of the Meter is signed by 17 nations, including the United States. This establishes a permanent body with the authority to set standards.

1893—The United States officially adopts the metric system standards as bases for weights and measures (but continues to use British units).

1975—The Metric Conversion Act is enacted by Congress. It states, “The policy of the United States shall be to coordinate and plan the increasing use of the metric system in the United States and to establish a voluntary conversion to metric system. (No mandatory requirements are made.

History information from: Introduction to Physical Science: Shipman, Wilson, Todd, 2000

Consistency.Consistency. Scientists use the Scientists use the International System International System

of Units (SI)of Units (SI) to make sharing data and to make sharing data and results easier.results easier.

SI Units

SI (Le Système Internationale SI (Le Système Internationale d’Unités)d’Unités)

SI prefixes for large measurementsSI prefixes for large measurements

SI Units for small measurementsSI Units for small measurements

Conversions Conversions A roll of copper wire A roll of copper wire contains 15 m of wire. What is the contains 15 m of wire. What is the length of the wire in centimeters?length of the wire in centimeters?

1. List the given and unknown values1. List the given and unknown values..

Given: Given: length in meters, llength in meters, l = 15 m = 15 mUnknown: Unknown: length in centimeters = ? length in centimeters = ? cmcm

2. 2. Determine the relationship between units.Determine the relationship between units.

Looking at the table of prefixes used Looking at the table of prefixes used for small for small measurements, you can find that:measurements, you can find that:

1 cm = 0.01 m. 1 cm = 0.01 m. Also means that 1 m = 100 cm. Also means that 1 m = 100 cm.

You will multiply because you are converting from a larger You will multiply because you are converting from a larger unit (meters) to a smaller unit (centimeters)unit (meters) to a smaller unit (centimeters)

3. Write the equation for the conversion3. Write the equation for the conversion..

length in cm length in cm = m = m

100 cm

1 m

4. Insert the known values into the equation, 4. Insert the known values into the equation, and solve.and solve.

length in cmlength in cm = 15 m = 15 m

100 cm

1 m

length in cm = 1500 cm

METRIC SYSTEM

LENGTH

Unit Abbreviation Number of

Meters Approximate U.S.

Equivalent

kilometer km 1,000 0.62 mile

hectometer hm 100 328.08 feet

dekameter dam 10 32.81 feet

meter m 1 39.37 inches

decimeter dm 0.1 3.94 inches

centimeter cm 0.01 0.39 inch

millimeter mm 0.001 0.039 inch

micrometer µm 0.000001 0.000039 inch

Divide by 10 or move one decimal place for each box to the left

Prefix kilo hecto Deka Meter deci centi milli

Abbreviation

k h Dk m dc

m

Examplekilomete

rhectomet

erdekamet

ermeter decimete

rcentimet

ermillimete

r

Multiplier 1,000 100 10 1 0.1 0.01 0.001

Multiply by 10 or move one decimal place for each box to the right

Interpret line graphs, bar graphs, and pie Interpret line graphs, bar graphs, and pie charts.charts.

Use scientific notation and significant figures Use scientific notation and significant figures in problem solving.in problem solving.

Identify the significant figures in calculations.Identify the significant figures in calculations.

Understand the difference between precision Understand the difference between precision and accuracy.and accuracy.

Chapter 1Organizing DataOrganizing Data

BellringerBellringerImagine your teacher asked you to study how Imagine your teacher asked you to study how providing different amounts of fertilizer affected providing different amounts of fertilizer affected the heights of plants. You perform a study and the heights of plants. You perform a study and collect the data shown in the table below. Use collect the data shown in the table below. Use this data to answer the items that follow.this data to answer the items that follow.

Chapter 1

Bellringer, Bellringer, continuedcontinued1. 1. Which amount of fertilizer produced the tallest plants?Which amount of fertilizer produced the tallest plants?2. 2. Which amount of fertilizer produced the smallest plants?Which amount of fertilizer produced the smallest plants?3. 3. Plot the data on a grid like the one below.Plot the data on a grid like the one below.4. 4. Describe the overall trend as more fertilizer is added to Describe the overall trend as more fertilizer is added to the plants.the plants.

Presenting Scientific DataPresenting Scientific Data

Line graphs are best for continuous change.Line graphs are best for continuous change.

• Line graphs are usually made with the x-axis Line graphs are usually made with the x-axis showing the independent variable and the y-axis showing the independent variable and the y-axis showing the dependent variable. showing the dependent variable.

• The values of the dependent variable depend on The values of the dependent variable depend on what happens in the experiment.what happens in the experiment.

• The values of the independent variable are set The values of the independent variable are set before the experiment takes place.before the experiment takes place.

Chapter 1

Line GraphLine Graph

Chapter 1

Presenting Scientific Data, Presenting Scientific Data, continuedcontinued

Bar graphs compare items.Bar graphs compare items.

• A bar graph is useful for comparing similar data A bar graph is useful for comparing similar data for several individual items or events.for several individual items or events.

• A bar graph can make clearer how large or small A bar graph can make clearer how large or small the differences in individual values are.the differences in individual values are.

Chapter 1

Bar GraphBar Graph

Chapter 1

Presenting Scientific Data, Presenting Scientific Data, continuedcontinued

Pie charts show Pie charts show parts of a whole.parts of a whole.

• A pie chart is ideal A pie chart is ideal for displaying data for displaying data that are parts of a that are parts of a whole.whole.

• Data in a pie chart Data in a pie chart is presented as a is presented as a percent.percent.

Graphing ActivityGraphing Activity

Significant Figures and Significant Figures and Scientific NotationsScientific Notations

Using Significant FiguresUsing Significant FiguresPrecision and accuracyPrecision and accuracy

Precision Precision the exactness of a measurementthe exactness of a measurement

Accuracy Accuracy a description of how close a a description of how close a measurement is to the true value of the quantity measurement is to the true value of the quantity measuredmeasured

Significant figure Significant figure a prescribed decimal place a prescribed decimal place that determines the amount of rounding off to be that determines the amount of rounding off to be done based on the precision of the measurementdone based on the precision of the measurement

Significant FiguresSignificant Figures

The The significant figuressignificant figures (also called (also called significant digitssignificant digits) of a number are ) of a number are

those those digits that carry meaning that carry meaning contributing to its accuracy. contributing to its accuracy.

Rules for identifying Rules for identifying significant digits significant digits

1.1. All non-zero digits are considered All non-zero digits are considered significant. significant.

Example: 123.45 has five significant Example: 123.45 has five significant figures: 1, 2, 3, 4 and 5. figures: 1, 2, 3, 4 and 5.

Zeros appearing anywhere Zeros appearing anywhere between two non-zero digits between two non-zero digits

are significant. are significant.

Example: 101.12 has five Example: 101.12 has five significant figures: 1, 0, 1, 1 and 2.significant figures: 1, 0, 1, 1 and 2.

Leading (space holding) Leading (space holding) zeros are not significant zeros are not significant

For example, 0.00012 has two For example, 0.00012 has two significant figures: 1 and 2. significant figures: 1 and 2.

Trailing zeros in a whole Trailing zeros in a whole number are NOT significant. number are NOT significant.

For exampleFor example

200 1200 125000 225000 210,100 310,100 3

When decimal point are present When decimal point are present at end of whole number, trailing at end of whole number, trailing

zeros ARE significantzeros ARE significant200. > 3200. > 3

25,000. > 525,000. > 510100. > 510100. > 5

Trailing zeros in a number Trailing zeros in a number containing a decimal point are containing a decimal point are

significant.significant.0.0500 > 30.0500 > 3

0.03040 > 40.03040 > 40.0230 > 30.0230 > 3

Addition and Subtraction:Addition and Subtraction:least number of digits to least number of digits to

right of decimal placeright of decimal place

Example: 24.46 2 digits Example: 24.46 2 digits + 6.123+ 6.123 3 digits 3 digits

30.58330.583 Rounds to: 30.58Rounds to: 30.58

Multiplication and Division:Multiplication and Division:Quantity which has the smaller Quantity which has the smaller number of significant figuresnumber of significant figures

Example: 2.61 x 1.2 = 3.13Example: 2.61 x 1.2 = 3.13 Rounds off to: 3.1Rounds off to: 3.112.34 x 1.23 = 15.178212.34 x 1.23 = 15.1782 Rounds off to: 15.2Rounds off to: 15.2

Rounding Rounding

Start with the leftmost non-zero digit (e.g. Start with the leftmost non-zero digit (e.g. the '1' in 1 200, or the '2' in 0.0256). the '1' in 1 200, or the '2' in 0.0256). Keep Keep nn digits. Replace the rest with zeros. digits. Replace the rest with zeros. Round up by one if appropriate. For Round up by one if appropriate. For example, if rounding 0.039 to 1 significant example, if rounding 0.039 to 1 significant figure, the result would be 0.04. figure, the result would be 0.04.

ExamplesExamples

Rounding to 2 significant figures:Rounding to 2 significant figures:12 300 becomes 12 000 12 300 becomes 12 000

13 stays as 13 13 stays as 13 0.00123 becomes 0.0012 0.00123 becomes 0.0012

0.1 becomes 0.10 (the trailing zero indicates that 0.1 becomes 0.10 (the trailing zero indicates that we are rounding to 2 significant figures). we are rounding to 2 significant figures).

0.02084 becomes 0.021 0.02084 becomes 0.021

Scientific NotationScientific Notation (standard form(standard form or or exponential notation)exponential notation)

Way of writing numbers that Way of writing numbers that accommodates values too large or accommodates values too large or small to be conveniently written in small to be conveniently written in

standard decimal notation. standard decimal notation.

Ordinary decimal Ordinary decimal notationnotation

Scientific Scientific notationnotation

11 1 × 101 × 1000

3030 3 × 103 × 1011

5 720 000 0005 720 000 000 5.72 × 105.72 × 1099

−−0.000 000 006 10.000 000 006 1 −−6.1 × 106.1 × 10−9−9

Using scientific notation,300,000,000 m/sec can also be written as

3 x 100,000,000or in the shorter form,

3 x 108,where 8, the exponent, is the number of

zeros.

Positive exponents/Large NumbersWritten in scientific notation by

moving the decimal point to the left. e.g. Avogadro's number is approximately

602,200,000,000,000,000,000,000Scientific notation : 6.022 x 1023

1. The decimal point is moved left to just after the first number 2. First number must be at least 1, but less than 103. In the example above, the decimal point has been moved

back by 23 places. That number is now the positive exponent of the base 10.

Negative exponents/Small NumbersNumbers less than 1 can be expressed in scientific

notation by moving the decimal point to the right. e.g. 0.0006022

Standard Notation: 6.022 x 10-4

1. First number must be at least 1, but less than 10. 2. For our e.g., decimal point needs to move forward by 4 digits to the first non-zero number

3. For every place we move the decimal to the right we decrease the power of ten by one.

Rule for Multiplication – 1. Multiply the coefficients2. Add the exponents. 3. The base will remain 10.

Rule for Division – 1. Divide the coefficients 2. Subtract the exponents. 3. The base will remain 10.

RULE #1: Standard Scientific Notation is a number from 1 to 9 followed by a decimal and the remaining

significant figures and an exponent of 10 to hold place value.

Example:

5.43 x 102 = 5.43 x 100 = 5438.65 x 10 – 3 = 8.65 x .001 = 0.00865****54.3 x 101 is not Standard Scientific

Notation!!!

RULE #2: When the decimal is moved to the Left the exponent gets Larger, but the value of the number stays the same. Each place the decimal moves Changes the

exponent by one (1). If you move the decimal to the Right it makes the exponent smaller by one (1) for each place it

is moved.

Example: 6000. x 100 = 600.0 x 101 = 60.00 x 102 =

6.000 x 103 = 6000(Note: 100 = 1)

All the previous numbers are equal, but only 6.000 x

103 is in proper Scientific Notation.

RULE #3: To add/subtract in scientific notation, the exponents must first be the same.

Example: (3.0 x 102) + (6.4 x 103); since 6.4 x 103 is equal to 64. x 102.

Now add.

(3.0 x 102) + (64. x 102)

67.0 x 102 = Not in scientific notation

6.70 x 103 = 6.7 x 10 3

67.0 x 102 is mathematically correct/standard scientific notation can only have one number to the left of the decimal

RULE #4: To multiply, find the product of the numbers, then add the

exponents.

Example: (2.4 x 102) (5.5 x 10 –4) =

[2.4 x 5.5 = 13.2] and [2 + -4 = -2]= 13.2 x 10 –2

Correct scientific notation: 1.3 x 10 – 1

RULE #5: To divide, find the quotient of the number and subtract the exponents.

Example:

(3.3 x 10 – 6) / (9.1 x 10 – 8) = ? [3.3 / 9.1 = .36] and [-6 – (-8) = 2]

(3.3 x 10 – 6) / (9.1 x 10 – 8) = .36 x 102 3.6 x 10 1

Scientific NotationScientific Notation

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80402.swf 80402.swf

Writing Numbers in Scientific Writing Numbers in Scientific NotationNotation

Using scientific notationUsing scientific notation

• When you use scientific notation in calculations, When you use scientific notation in calculations, you follow the math rules for powers of 10.you follow the math rules for powers of 10.

• When you multiply two values in scientific When you multiply two values in scientific notation, you add the powers of 10. When you notation, you add the powers of 10. When you divide, you subtract the powers of 10.divide, you subtract the powers of 10.

Chapter 1

Math SkillsMath Skills

Writing Scientific Notation Writing Scientific Notation The adult human The adult human heart pumps about 18 000 L of blood each heart pumps about 18 000 L of blood each day. Write this value in scientific notation.day. Write this value in scientific notation.

1. List the given and unknown values.1. List the given and unknown values.Given: Given: volume, Vvolume, V = 18 000 L = 18 000 LUnknown: Unknown: volume, V = ? x 10volume, V = ? x 10?? L L

Chapter 1


2. Write the form for scientific notation.2. Write the form for scientific notation.VV = ? x 10 = ? x 10?? L L

3. Insert the known values into the form, 3. Insert the known values into the form, and solve.and solve.First find the largest power of 10 that will divide First find the largest power of 10 that will divide

into the known value and leave one digit before into the known value and leave one digit before the decimal point. You get 1.8 if you divide 10 the decimal point. You get 1.8 if you divide 10 000 into 18 000 L. 000 into 18 000 L.

So, 18 000 L can be written as (1.8 x 10 000) LSo, 18 000 L can be written as (1.8 x 10 000) L

Chapter 1


Then write 10 000 as a power of 10. Then write 10 000 as a power of 10. Because 10 000 = 10Because 10 000 = 1044, you can write 18 000 L as , you can write 18 000 L as

1.8 x 101.8 x 1044 L. L.

Chapter 1

V = 1.8 x 104 L


Using Scientific Notation Using Scientific Notation Your state plans to Your state plans to buy a rectangular tract of land measuring buy a rectangular tract of land measuring 5.36 x 105.36 x 1033 m by 1.38 x 10 m by 1.38 x 1044 m to establish a m to establish a nature preserve. What is the area of this nature preserve. What is the area of this tract in square meters?tract in square meters?

1. List the given and unknown values.1. List the given and unknown values.Given: Given: length, llength, l = 1.38 x 10 = 1.38 x 1044 m m

width, wwidth, w = 5.36 x 10 = 5.36 x 1033 m m

Unknown: Unknown: area, A = ? marea, A = ? m22

Chapter 1

Math Skills, Math Skills, continuedcontinued

2. Write the equation for area.2. Write the equation for area.A = l A = l w w

3. Insert the known values into the equation, and 3. Insert the known values into the equation, and solve.solve.A = (1.38 A = (1.38 10 1044 m) (5.36 m) (5.36 10 1033 m) m)Regroup the values and units as follows.Regroup the values and units as follows.A = (1.38 A = (1.38 5.36) (10 5.36) (1044 10 1033) (m ) (m m) m)

When multiplying, add the powers of 10.When multiplying, add the powers of 10.A = (1.38 A = (1.38 5.35) (10 5.35) (104+34+3) (m ) (m m) m)A = 7.3968 A = 7.3968 10 1077 m m22

A = 7.40 A = 7.40 10 1077 m m22

Precision and accuracyPrecision and accuracy

Precision Precision the exactness of a the exactness of a measurementmeasurement

Accuracy Accuracy a description of how a description of how close a measurement is to the close a measurement is to the true value of the quantity true value of the quantity measuredmeasured

Accuracy and Precision, part Accuracy and Precision, part 11

Section 3 Organizing DataChapter 1

Accuracy and Precision, part Accuracy and Precision, part 22


Accuracy and PrecisionAccuracy and Precision


Using Significant FiguresUsing Significant Figures

When you use measurements in When you use measurements in calculations, the answer is only as precise as calculations, the answer is only as precise as the least precise measurement used in the the least precise measurement used in the calculation.calculation.

The measurement with the fewest significant The measurement with the fewest significant figures determines the number of significant figures determines the number of significant figures that can be used in the answer.figures that can be used in the answer.

Chapter 1

Math SkillsMath SkillsSignificant Figures Significant Figures Calculate the volume of a Calculate the volume of a

room that is 3.125 m high, 4.25 m wide, and room that is 3.125 m high, 4.25 m wide, and 5.75 m long. Write the answer with the 5.75 m long. Write the answer with the correct number of significant figures.correct number of significant figures.

1. List the given and unknown values.1. List the given and unknown values.Given: Given: length, llength, l = 5.75 m = 5.75 m

width, wwidth, w = 4.25 m = 4.25 m

height, hheight, h = 3.125 m = 3.125 m

Unknown: Unknown: Volume, V = ? mVolume, V = ? m33

Chapter 1

Math Skills, Math Skills, continuedcontinued

2. Write the equation for volume.2. Write the equation for volume.V = l V = l w w h h

3. Insert the known values into the 3. Insert the known values into the equation, and solve.equation, and solve.V = 5.75 m V = 5.75 m 4.25 m 4.25 m 3.125 m 3.125 mV = 76.367 1875 mV = 76.367 1875 m33

The answer should have three significant figures, The answer should have three significant figures, because the value with the smallest number of because the value with the smallest number of significant figures has three significant figures.significant figures has three significant figures.

Chapter 1

V = 76.4 mV = 76.4 m33

Understanding ConceptsUnderstanding Concepts1. 1. During a storm, rainwater depth is measured During a storm, rainwater depth is measured

every 15 minutes. Which of these terms every 15 minutes. Which of these terms describes the depth of the water?describes the depth of the water?

A.A. controlled variablecontrolled variableB.B. dependent variabledependent variableC.C. independent variableindependent variableD.D. significant variablesignificant variable

Understanding ConceptsUnderstanding Concepts

2. 2. Why were scientists unable to form a theory that Why were scientists unable to form a theory that diseases are caused by bacteria before the late diseases are caused by bacteria before the late fifteenth century?fifteenth century?

F.F. No on tried to understand the cause of disease until No on tried to understand the cause of disease until then.then.G.G. Earlier scientists were not intelligent enough to Earlier scientists were not intelligent enough to understand the existence of bacteria.understand the existence of bacteria.H.H. The existence of microbes could not be discovered The existence of microbes could not be discovered until the technology to make high-quality lenses had until the technology to make high-quality lenses had been been developed.developed.I.I. Doctors believed they understood the disease Doctors believed they understood the disease process, process, so they would not accept new ideas about so they would not accept new ideas about the causesthe causes..

Chapter 1

Understanding ConceptsUnderstanding Concepts

3. 3. What is a scientific theory?What is a scientific theory?

A.A. A theory is a guess as to what will happen.A theory is a guess as to what will happen.B.B. A theory is a summary of a scientific fact A theory is a summary of a scientific fact based based on observations.on observations.C.C. A theory is an explanation of how a process A theory is an explanation of how a process

works based on observations.works based on observations.D.D. A theory describes a process in nature that A theory describes a process in nature that can can be repeated by testing.be repeated by testing.

Interpreting GraphicsInterpreting Graphics

4. 4. What is the What is the volume of the gas volume of the gas 40 seconds into 40 seconds into the experiment?the experiment?

F.F. 15 mL15 mLG.G. 24 mL24 mLH.H. 27 mL27 mLI.I. 50 mL50 mL

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