Scientific Method

1. Notes Scientific Method How Scientists Work

2. How Scientists Work:Solving the Problems • Much of biology deals with solving problems • These problems can be environmental, ecological, health related, etc. • No matter what types of problemsare being studied, scientists use the same problem-solving steps called… • The Scientific Method

3. Question What does the scientist want to learn more about? First Then Research Gathering of information Scientific Method An Overview 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 Information collected during the experiment And And Observations Written description of what was noticed during the experiment Finally Conclusion Was the hypothesis correct or incorrect?

4. Scientific Method Ask Question • Let’s break each of these steps down into their individual components: Do Background Research Think! Try Again Construct Hypothesis Test with an Experiment Analyze Results Draw Conclusion Hypothesis is True Hypothesis is False or Partially True Report Results

5. As we all know, frogs have four legs. What’s up with thesefroggies? 1. Observing • Make an observation • See somethingunusual • Frogs withincorrectnumber oflegs!

6. 2. Questioning • Recognize, state or define the problem • Must be in the form of a question • The obvious question is:  • What is causing these deformities?

7. 3. Researching • Gather information related to the problem • Read, observe, measure, take samples, etc. • How frogs normally develop from eggs • The % of frogs with the deformities • Number of other species in the pond with deformities • Previous or new pollutantsin the pond • Change in amount of UV (sunlight) exposure on eggs • Etc.

8. 4. Hypothesizing • A hypothesis is: • An educated guess, trial answer, possible solution, prediction • Must be a statement • Must be testable or measurable • Is based on your research and previous experience

9. Hypothesizing • List possible explanations (alternative hypotheses) based on your previous experience (what you already know);  and on research you have done   • all of the hypotheses must be testable (no demons allowed!)

10. Hypothesizing • Some possible explanations (hypotheses) for the frog deformities: Genetic mutation Chemical Pollution Ultraviolet Radiation Disease (virus or parasite or...?) Loud Rock & Roll Music Aliens from outer space Something else

11. Hypotheses' usually come in the form of “If …. then …..” statements Ex: Question: “How does the size of a wheel affect the speed of a HotWheels car?” Hypothesis: “If the car has large wheels, then its speed will be slower.”

12. 5. Experimenting • Testing the hypothesis • Pick the hypothesis that makes the most sense and is easy to test • Then design a controlled experiment

13. Experimenting • This is a real experiment that was carried out using the scientific method.

14. Control and Experimental Groups Control group: • used as a standard of comparison • the group containing the factor (variable) that has been changed Experimental group: (manipulated or independent variable)

15. Variables in an Experiment • Variables - Factors that can be changed • Controlled Variables- all the variables that remain constant • Independent Variable(manipulated variable) - factor in an experiment that a scientist purposely changes • Dependent Variable (aka Responding Variable) - the outcome or results, the factor in an experiment that may change because of the manipulated variable….what a scientist wants to observe

16. Setting up a Controlled Experiment • In a controlled experiment, only one factor is changed at a time. • Independent variable: the factor that is deliberately changed • Dependent variable: the factor that the scientist wants to observe; it changes in response to the independent variable

17. 6. Collect and Record Data Data: observations and measurementsmade in an experiment Types of Recorded Data • Quantitative - observations that involve measurements/numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters • Qualitative - observations thatdo not involve numbers, are of a descriptive naturei.e. white maggots covered the meat, leaves were all wilting

18. Data is based on facts, not assumptions! • Fact: something that has actual existence; can be proven to be true • “School on a normal day at Cleveland HS starts at 7:57 am.” • Assumption: a notion taken for granted, usually based on some factual evidence • “At Nobel MS, we got out early every Tuesday so it’s the same at Cleveland HS.”

19. 7. Analyze the Data • Examine data tables, charts, and graphs • Examine experimental notes • Look for trends, patterns, and averages • What does the data show • Put your data into words

20. 8. Draw Conclusions • Collected data is analyzed and one comes up with a conclusion by deduction (deriving of a conclusion by reasoning) • Support your conclusion with specific, numerical data. Accept or reject the hypothesis.

21. 9. Publishing Results • Results of an experiment are useful only if they are made available to other scientists so they can verify results • If no one knows about it, no one can prove or disprove it • Unless another scientist can reproduce the experiment with the same results, may become an inference (act of passing statistical sample data general conclusion) that may be incorrect • Anti-wrinkle creams • Weight loss drugs • Anti-aging pills

22. Why is Publication Necessary? • Which European is credited with “discovering” North America? • Christopher Columbus • Which European peoples really “discovered” North America? • Vikings • Why did Columbus get the credit? • Columbus told everyone who would listen, whereas the Vikings kept it secret

23. 10. Forming a Theory • A theory is a hypothesis that is supported by a large (humungous) body of scientific evidence • only after evidence is collected, tested by different individuals many times, and published can a hypothesis become a theory

24. Hypothesis vs. Theory vs. Law • What’s the difference between a hypothesis, a theory, and a scientific law? • hypothesis: educated guess that has no proof • “I am the best teacher at Cleveland High School.” • theory: hypothesis that is proven correct • “Smoking Causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy.” • scientific law: true and universal fact • “What goes up, must come down.”