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Scientific Method (1)

Scientific Method (1) - Notes Notes Scientific Method...

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Unformatted text preview: Notes Notes Scientific Method Scientific Chapter 1: Section 2 How Scientists Work Lecture Outline – The Scientific Method PowerPoint Notes textbook questions Keys Keys How Scientists Work: How Solving the Problems Solving Much of biology deals with solving Much problems problems These problems can be environmental, These ecological, health related, etc. ecological, No matter what types of problems are being studied, scientists use are the same problem-solving steps called… called… The Scientific Method Scientific Method Scientific Definition The scientific method isThe scientific A llogical and systematic approach or ogical process to problem solving. An organized way of using evidence An to learn about the natural world. According to Wikipedia - Scientific method is a body Scientific of techniques for investigating phenomena and acquiring phenomena new knowledge, as well as for correcting and integrating knowledge as previous knowledge. It is based on gathering observable observable , empirical and measurable evidence subject to specific empirical measurable evidence principles of reasoning, the collection of data through reasoning the observation and experimentation, and the formulation observation experimentation and and testing of hypotheses. hypotheses Scientific Method Scientific Listing the Steps Listing Make an Observation Define the Problem Research the Problem State the Hypothesis Experiment to test Hypothesis Collect and Record Data Analyze Data Draw Conclusions Determine Limitations Report Results If needed, Do more investigation S C I M EE T N H TO D I O V E R V I E W First Question What does the scientist want to learn more about? Then Research Scientific Method An Overview Gathering of information Next Hypothesis An “Educated” guess of an answer to the question Then Procedure/ Method Written and carefully followed step-by-step experiment designed to test the hypothesis Next Data And Observations Information collected during the experiment And Written description of what was noticed during the experiment Finally Conclusion Was the hypothesis correct or incorrect? First Question What does the scientist want What does the scientist want to learn more about? to learn Then Research Scientific Method An Overview Gathering of information of information Next Hypothesis An “Educated” guess of an An “Educated” guess of an answer to the question answer Then Procedure/ Method Written and carefully Written followed step-by-step followed step-by-step experiment designed to test experiment designed to test the hypothesis the hypothesis Next Data And Observations Information collected during Information collected during the experiment the experiment And Written description of what Written description of was noticed during the was noticed during the experiment experiment Finally Conclusion Was the hypothesis correct Was the hypothesis correct or incorrect? or incorrect? Hypothesis (Conclusions) M EE T N H TO D I Procedures I Scientific Method (Experiments) C O V E R V I E W Findings S Data (Results) Repeat steps 3-7 for competing hypotheses. Competing hypotheses may include revisions of the original hypothesis suggested by the results of the testing process. S Here is another Here example of how the O C steps may go…. steps V Even though we Even E show the scientific I method as a series M R in of steps, keep E that V mind E new information or T I thinking might N cause a scientist to H E back up and repeat stepsO any W point T at during the process. during D I Make Observations Form a Define / Identify H Problem the ypothesis Test Hypothesis Perform Experiments New Experiments Organize and Analyze Data NO Do Experiments and Observations Support Hypothesis? Faulty Experiments? YES Communicate Results Draw Valid Conclusions Scientific Method Scientific Let’s break Let’s each of these steps down into their individual components: components: Scientific Method Scientific Let’s break Let’s each of these steps down into their individual components: components: Ask Question Do Background Research Construct Hypothesis Think! Try Again Test with an Experiment Analyze Results Draw Conclusion Hypothesis is True Hypothesis is False or Partially True Report Results 1. Observing 1. As we all know, frogs have four legs. Make an Make observation observation See See something something unusual Frogs with incorrect number of legs! What’s up with these froggies? 2. Questioning 2. Recognize, state or define the Recognize, problem problem Must be in the form of a question Must The obvious question is: The What is causing these deformities? What 3. Researching 3. Gather information related to the problem Read, observe, measure, take samples, etc. How frogs normally develop from eggs The % of frogs with the The deformities deformities Number of other species in Number the pond with deformities the Previous or new pollutants in the pond Change in amount of UV Change (sunlight) exposure on eggs Etc. Etc. 4. Hypothesizing A hypothesis is: An educated guess, trial answer, possible An solution, prediction solution, Must be a statement Must be testable or measurable Is based on your research Is and previous experience and Hypothesizing List possible explanations (alternative List hypotheses) based on your previous experience (what you already know); and on research you have done all of the hypotheses must be testable all (no demons allowed!) Hypothesizing oud RockRadiationAomething ElseSSome (virus, parasite, Chemical outer Gisease mutation-Music- (hypotheses) enetic UltravioletPollutionDSome possible explanationsetc.)L liens from+ Roll spaceor thehypothesis is true, then: frog deformities: Ifftthishypothesis is true, then: think of IfGenetic mutation his Another possibility that we might Genetic You shouldbe able to to find thethen: should If this hypothesis is a likely disease-causing Wepredation able find true, chemical pollutant in Iif orry, be or cannibalism, which seems SChemical frog ponds sChemical the deformed Pollution agent matebe able to measure at the deformed Webe theexample, isolate the chemical from high should best to parasites) unusually the pond Itfowe (for this explanation for certain kinds You should bedeformed frogs the offspring ableis testable, Okay,UV radiation at deformed frog sites t hould Ultraviolet U fevels of show similar deformities l rogltraviolet Radiation shis is not allowed because waterponds o e should be able to find these same levels to Wf deformities (frogs with parasiteschemical the missing limbs). use bouis WHY testparasite then, at minimum: Y heshould be testable using the the Disease (virustoshould beor...?) uniform Disease able or it??? fairly in T utdeformities show that the isolated inducenot exactsame deformities in the lab in the t this hypothesis is kinds of deformities dan cause the c iIfeformed frogs same true, the exact Loud Rock L should be able to use the agetare minimalMethod. same parasite to nd should find frogs and/or other already predictable (abeoudreal)& Roll Music you may havepond These Wcientific predictions; We S l The you think of deformities should onlyin the hought of the fact same predictions based have Aliens A particular other kinds itnduce the exactthat chemical pollution legs on be critters from outer space of deformities this Canliens with evidence that their should affect aound in one species ll heesh! Seen limbs equally, or that other organisms from the fabfour damaged or bitten off lbypothesis? else Something hame ponds should show deformities as well Something s 5. Experimenting 5. Testing the hypothesis Pick the hypothesis that makes the most Pick sense and is easy to test easy Then design a Then controlled experiment experiment Experimenting Experimenting Go to the web site for Hartwick College to Go see the experiments and how the scientific method was actually used to find out the cause of recently found frog deformities. found http://www.hartwick.edu/biology/def_frogs/I ntroduction/Exploration/explore.html Experimenting Experimenting Let’s look at the text book example of Let’s the Scientific Method using Redi’s Experiment on Spontaneous Generation on He was trying to disprove He the idea of Spontaneous the Generation (or actually Generation that flies came from that maggots, which came from flies) Francesco Redi (1668) Francesco (1668) Stating the Problem Stating Example: How do new living Example: things come into being? things Spontaneous generation once Spontaneous commonly accepted commonly Redi wanted to show what Redi caused the appearance of maggots (and then flies) on meat maggots Belief based on prior observations prior If leaf lands on water it becomes a fish If bale of hay left in barn it produces mice Muddy soil gives rise to frogs Meat hung out in the market is the source Meat of flies of Belief based on prior observations prior Redi observed that maggots appeared Redi on meat a few days after flies were on meat meat No microscope = no way to see eggs But Redi believed that maggots came But from eggs that were laid by flies from Forming a Hypothesis Forming Redi’s Hypothesis: Redi’s Flies produce maggots. Flies How could he test this? Through a controlled experiment Redi’s Controlled Redi’s Experiment Redi used two groups of jars Jars that contained meat and no cover Jars that contained meat and gauze cover Jars with meat Uncovered jars Covered jars Control and Experimental Groups Groups Control group: used as a standard of Control comparison Experimental group: the group containing Experimental the factor (variable) that has been changed the (manipulated or independent variable) Two groups of jars Uncovered jars Covered jars Variables in an Experiment Variables Variables - Factors that can be changed Variables Factors Controlled Variables - all the variables that Controlled remain constant Manipulated Variable - (also called the Manipulated Independent Variable) - factor in an experiment Independent that a scientist purposely changes that Responding Variable- (also called the (also Responding Dependent Variable) - the outcome or results, the Dependent factor in an experiment that may change because of the manipulated variable…. of what a scientist wants to observe Setting up a Controlled Experiment Experiment In a controlled experiment, In controlled only one factor is changed at a time. time. Independent variable: the factor that is deliberately changed changed Dependent variable: the factor that the scientist wants to observe; it changes in response to the independent variable independent Variables in Redi’s Variables Experiment Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Let’s think about this.… Let’s 1. Which is the control group? Uncovered jars 2. Which is the experimental group? Two groups of Jars with meat Uncovered jars Covered jars Covered jars Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Covered jars Uncovered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. 6. Collect and Record Data 6. Data: observations and measurements Data: made in an experiment Types of Recorded Data Types Quantitative - observations that Quantitative involve measurements/numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters liters Qualitative - observations that Qualitative observations do not involve numbers, are of a do descriptive nature descriptive ii.e. white maggots covered the .e. meat, leaves were all wilting 7. Analyze the Data 7. Examine data tables, Examine charts, and graphs charts, Examine experimental Examine notes notes Look for trends, patterns, Look and averages and What does the data show Put your data into words 8. Draw Conclusions 8. Restate the hypothesis: Example: Flies produce maggots. Accept or reject the hypothesis. Support your conclusion with specific, numerical data. Support What was Redi’s conclusion? Flies lay eggs too small to be seen. Maggots found on rotting meat are produced from the eggs laid by flies. Maggots are not appearing due to Maggots spontaneous generation! generation! 9. Determine Limitations 9. Scientists look for possible Scientists flaws in their research flaws They look for faulty They (inaccurate) data (inaccurate) They look for experimental They error or bias's They decide on the validity They of their results of They make suggestions for improvement or They raise new questions raise 10. Publish Results Communication is an Communication essential part of science essential Redi’s experiment on insects generation Scientists report their Scientists results in journals, on the internet, or at conferences at This allows their This experiments to be evaluated and repeated evaluated Scientists can build on previous Scientists work of other scientists work Repeating the Investigation Repeating Sometimes results are unexpected. Repeat the experiment! John Needham challenged Redi’s experiment John and designed his own to show that spontaneous generation CAN occur under certain circumstances. certain Lazzaro Spallanzini Lazzaro designed a slightly different experiment to improve on Needham’s work Needham’s Repeating the Experiment Repeating (continued) Louis Pasteur further modified the Louis experiment. experiment. Scientific Method How Scientists Work Solving the Problems The reason scientific work is called “RE-search” rather than just "search " is because it is an ongoing process that often times changes our view of the natural world. It is subject to modification in light of new evidence and new ways of thinking. S C I E N T I M E T H O D R E V I E W Can you put these steps in order? steps 2 7 Define the Problem 5 10 Analyze Data 4 8 9 3 Report Results 1 6 Make an Observation State the Hypothesis Determine Limitations the Problem Steps of Scientific Steps Method in order 1 2 Make an Observation Define the Problem 6 7 Analyze Data 4 3 the Problem 8 5 State the Hypothesis 9 10 Determine Limitations Report Results Scientific Theory Scientific A theory is an theory explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers Scientific Law Scientific Scientific laws represent Scientific the cornerstone the of scientific discovery They must be simple, They true, universal, and absolute If a law ever did not If apply, then all science based upon that law would collapse Scientific Method ...
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