UNIT ONE: Habits of Mind. How scientists work. No matter what types of problems are being studied, scientists use the same problem-solving steps called the scientific method . The scientific method is A logical and systematic approach or process to problem-solving. - PowerPoint PPT Presentation
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UNIT ONE:Habits of MindNo matter what types of problems are being studied, scientists use the same problem-solving steps called the scientific method.The scientific method isA logical and systematic approach or process to problem-solving.An organized way of using evidence to learn about the natural world.How scientists workMake an observation.Define the problem.Research the problem.State the hypothesis.Experiment to test the hypothesis.Collect and record data.Analyze the data.Draw conclusions.Report results.Listing the stepsThenAndQuestionResearchHypothesisProcedure/MethodDataObservationsConclusionWhat does the scientist wantto learn more about?Gathering of informationAn Educated guess of ananswer to the questionWritten and carefullyfollowed step-by-stepexperiment designed to testthe hypothesisInformation collected duringthe experimentWritten description of whatwas noticed during theexperimentWas the hypothesis correct or incorrect?NextThenNextAndFinallyFirstScientific MethodAn OverviewQuestion: What will happen to the magnesium metal if I drop hydrochloric acid into the test tube? Scientific MethodAsk QuestionDo BackgroundResearchConstructHypothesisTest with anExperimentAnalyze ResultsDraw ConclusionThink!Try AgainReport ResultsHypothesis is TrueHypothesis is Falseor Partially TrueAristotle proposed that living things can be generated from non-living things, and his theory is called Spontaneous Generation in 322 BC.People accepted the idea.Francesco Redi disagreed in 1668. He was trying to disprove the idea of Spontaneous Generation using fruit flies.WAITpeople believed this for 1668 + 322 years!
Redis experiment on Spontaneous GenerationMaggots occur on meat after a few days.Make an observationHow did the maggots get on the meat?Define the problem.Redi observed that maggots appeared on the meat after a few days.He believed that flies landed on the meat, laid eggs, and the eggs hatched.Research the problem.Flies produce maggots.State the hypothesis
Redi set up a controlled experiment. Others have used his experiment as a model for setting up their own experiments for many years.Experiment to test the hypothesis
Control GroupExperimental GroupControl Group: used as a standard of comparisonJars with meat and no coverControl variables: same jars, same type of meat, same location, same temperature, same amount of time (MANY)
Experimental group: Jars with meat and a gauze coverManipulated variable: gauze covering the jar (ONLY ONE)Dependent variable: whether maggots appear or not (RESULT)Important vocabulary & Concepts
Redi recorded the size jar, type of meat, amount of meat, location of meat, temperature of room, time passed, type of gauze used, changes in meat each day, and when/if maggots appeared.Maggots only appeared on the meat in the uncovered jars after a few days. No maggots appeared on the meat in the covered jars.Types of Data: Quantitative: involves numbers; often graphedQualitative: does not involve numbersCollect DataRedi reviewed his hypothesis: Flies produce maggots.He accepted the hypothesis because of the data.Flies must have laid eggs that are too small to be seen.Flies could not get to the covered meat to lay their eggs.Maggots did not spontaneously generate on the meat.EVIDENCE was necessary to disprove Aristotles claim. Data IS evidence.Draw conclusionsRedi looked over his work carefully. He tried to identify mistakes in his experiment. Could there be another explanation for his results?He looked for ways to improve his experiment.He decided if it was necessary to repeat the experiment with the improvements.Determine limitationsWhen Redi was satisfied with his results, he wrote a report of the experiment outlining all of the information that weve discussed.He published that report in 1668 in a book.Other scientists repeated his experiment to check his work, and finally the theory of spontaneous generation was disproved.Report resultsVariables - Factors that can be changedControlled Variables - all the variables that remain constant Independent Variable - (also called the Manipulated Variable) - factor in an experiment that a scientist purposely changes Dependent Variable- (also called the Responding Variable) - the outcome or results, factor in an experiment that may change because of the manipulated variable.what a scientist wants to measure or observeGraphing Rule: Graph the dependent variable on the Y-axis. The independent variable goes on the X-axis.
Review of experimental variable vocabulary
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.HYPOTHESIS: Flies produce maggots.PROCEDUREManipulated Variables:gauze covering thatkeeps flies away from meatUncovered jarsCovered jarsSeveral days passMaggots appearNo maggots appearResponding Variable: whether maggots appearCONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.Controlled Variables:jars, type of meat,location, temperature,timeUsually quantitative data is measured with an instrument in the lab.Scientists use the metric system units.
Gathering quantitative dataMeasurementEquipment UsedMetric Base UnitLengthMetric ruler or meter stickMetersMassBalanceGramVolume of a liquidGraduated cylinderLiterTimeStopwatch or second hand on clocksecondThe metric system is based upon powers of ten. Prefixes are added to the base units to make larger or smaller units.Example: milli, kilo, or deciSince our number system is also based on powers of ten, converting from one metric prefix to another is as simple as moving a decimal.Memory device: King Henry died by drinking chocolate milk.
Metric system prefixes & conversionsKiloHectoDecaBASEDeciCentiMilliKhDMeterLiterGramdcm1000100101.1.01.001Conversion examplesConvert 145.8 cm to mm. 1458 mmConvert 3.4 kg to dg.34,000 dgConvert 13,499 mL to hL.0.13499 hLFor homework tonight, complete the metric mania worksheet.Metric system prefixes & conversionsKiloHectoDecaBASEDeciCentiMilliKhDMeterLiterGramdcm103102101110-110-210-3Biology is the study of life!Are Flames Alive?All living things have 8 characteristics in common.Made of one or more cellsDisplays organizationGrows & develops (increase in mass & gains new abilities)ReproducesResponds to stimuli (ex. heat, light, weather)Requires energyMaintains homeostasis (stable internal conditions)Adaptations evolve over time (help species survive)
Characteristics of Living ThingsLevels of OrganizationOrganismsOrgan systemsOrgansTissuesCellsMoleculesAtoms