2What is the scientific method….. ?The scientific method is a ______ for answering questions.process
3SCIENTIFIC METHODA series of steps that scientists use to answer questions and solve problems.Is not a rigid procedure.Scientists may use all of the steps or just some of the steps.They may even repeat some of the steps.The goal of the scientific method is to come up with reliable answers and solutions to questions.
4Steps in the Scientific Method ObservationDefine a problemHypothesisExperimentData Collection/analysisConclusionRetest
5Observations Gathered through your senses A scientist notices something in their natural world
6ObservationsAn example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails
7Define a problemThe scientific method starts with observations that lead to questions…defining a problem. (5 Senses)How, What, When, Where, why?Initial observations and inferences.
8Hypothesis A suggested solution to the problem. Must be testable Sometimes written as If…Then… statementsPredicts an outcome***A hypothesis is a testable explanation for an answer to an observation, question or problem.
9HypothesisAn example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.
10A valid hypothesis has three characteristics 1. Testable2. Unbiased3. RepeatableIf a hypothesis satisfies these criteria it can be accepted as a Scientific Theory*
11A procedure to test the hypothesis. ExperimentA procedure to test the hypothesis.
12Variable – factor in the experiment that is being tested
13ExperimentA good or “valid” experiment will only have ONE variable! (meaning only one thing is changed at a time)
15Scientific Experiments Follow Rules An experimenter changes one factor (Independent variable) and observes or measures what happens (dependent variable).
16The Control VariableThe experimenter makes a special effort to keep other factors constant so that they will not effect the outcome.Those factors are called control variables.
17What is the Purpose of a Control? Controls are NOT being testedControls are used for COMPARISON
18Other VariablesThe factor that is changed is known as the independent variable. It is graphed on the x axis. (I Do)The factor that is measured or observed is called the dependent variable. It is graphed on the y axis. (Data)
19Example of Controls & Variables For example, suppose you want to figure out the fastest route to walk home from school.You will try several different routes and time how long it takes you to get home by each one.Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.
20What are the Variables in Your Experiment? Varying the route is the independent variableThe time it takes is the dependent variableKeeping the same walker throughout makes the walker a control variable.
21One more thing… it is best to make several trials with each independent variable.
29Solving a Problem 1)Identify a Problem 2) State Observations about the problem3) Form a Hypothesis about the problem (if…then…)4) Design an Experiment to test the hypothesis5) Collect Data6) Form a Conclusion7) Retest
30Scientific Theory vs. Law What is the difference?
31Scientific Theory vs. Law Explanation for an observation that is confirmed by a large amount of evidence or tests (experiments).Example:Germ theory of disease - Infectious diseases result from the action of microorganisms.LAWA statement of a scientific principle that appears to be without exception at the time it is made, and always works the same way under thesame conditions; A scientific rule.Newton's First Law of Motion (Law of Inertia) - every object either remains at rest or in continuous motion with constant speed unless acted upon by an outside force.Treponema pallidum -♪ (Trep-o-neemah pal-lid-um)
32So, what's the difference? A SCIENTIFIC THEORY- are typically non-mathematical.A SCIENTIFIC LAW- are often mathematically definedLooking at things this way helps to explain, in part, why physics and chemistry have lots of "laws" whereas biology has few laws (and more theories).In biology, it is very difficult to describe all the complexities of life with "simple" (relatively speaking!) mathematical terms.
33Scientific Theory vs Law How are they the same? both are based on tested hypothesesboth are supported by a large body of empirical databoth help unify a particular fieldboth are widely accepted by the vast majority (if not all) scientists within a discipline.both scientific laws and scientific theories are true based on what we know today – but they can be changed with new information.
34What is the study of living things? Name the characteristics of living things and define three of them.Extra credit: What does DNA stand for… spell it correctly.
35Table of contents1 8/20 intro bell ringer, SM, metric2 8/22 What is living3. 8/23 Learning Targets4. 8/23 Characteristics of organisms (circles)5. 8/28 What is Biology6. 8/29 Scientific Method7. 8/23 Safety (I have until next week)8. 8/30 Quiz 1… characteristics/30 Prefix list and worksheet