1. How Scientists Work How do scientists test hypotheses?
How does a scientific theory develop?

2. Objectives
SPI 3210 Inq.1 Select a description or scenario that reevaluates and/or extends a scientific finding.
SPI 3210 Inq.2 Analyze the components of a properly designed scientific investigation.
SPI 3210 Inq.5 Defend a conclusion based on scientific evidence.

3. Chimpanzees and Humans
You and your partner, determine your roles

4. Inquiry Inquiry is the search for information and explanation
Scientists begin an inquiry investigation with a question
There are two main types of scientific inquiry: discovery science and hypothesis-based science
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5. Discovery Science
Discovery science describes natural structures and processes
This approach is based on observation and the analysis of data
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6. Types of Data Data are recorded observations or items of information
Data fall into two categories
Qualitative, or descriptions rather than measurements
Quantitative, or recorded measurements, which are sometimes organized into tables and graphs
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7. Fig. 1-23
Figure 1.23 Jane Goodall collecting qualitative data on chimpanzee behavior 7

8. Induction in Discovery Science
Inductive reasoning draws conclusions through the logical process of induction
Repeat specific observations can lead to important generalizations
For example, “the sun always rises in the east”
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9. Deduction: The “If…Then” Logic of Hypothesis Based Science
Deductive reasoning uses general premises to make specific predictions
For example, if organisms are made of cells (premise 1), and humans are organisms (premise 2), then humans are composed of cells (deductive prediction)
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10. Partner time
Humans: describe the difference between inductive and deductive reasoning to your partner
Chimpanzees: Review the difference between quantitative and qualitative data

11. Objectives
SPI 3210 Inq.1 Select a description or scenario that reevaluates and/or extends a scientific finding.
SPI 3210 Inq.2 Analyze the components of a properly designed scientific investigation.
SPI 3210 Inq.5 Defend a conclusion based on scientific evidence.

12. A Closer Look at Hypotheses in Scientific Inquiry
A hypothesis must be testable and falsifiable
Hypothesis-based science often makes use of two or more alternative hypotheses
Failure to falsify a hypothesis does not prove that hypothesis
For example, you replace your flashlight bulb, and it now works; this supports the hypothesis that your bulb was burnt out, but does not prove it (perhaps the first bulb was inserted incorrectly)
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13. The Myth of the Scientific Method
The scientific method is an idealized process of inquiry
Hypothesis-based science is based on the “textbook” scientific method but rarely follows all the ordered steps
Discovery science has made important contributions with very little dependence on the so-called scientific method
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14. Scientific Method Stating the Problem
How do new living things, or organisms, come into being?
Forming a Hypothesis
Francesco Redi questioned the theory of spontaneous generation
flies produce maggots

15. Scientific Method Setting Up a Controlled Experiment
Recording and Analyzing Results
Drawing a Conclusion
Publishing and Repeating Investigations

16. Objectives
SPI 3210 Inq.1 Select a description or scenario that reevaluates and/or extends a scientific finding.
SPI 3210 Inq.2 Analyze the components of a properly designed scientific investigation.
SPI 3210 Inq.5 Defend a conclusion based on scientific evidence.

17. Partner time
Humans: Tell your partner the two things that make a valid hypothesis
Chimpanzees: Walk through the steps of the scientific method
Chimps and humans together: discuss how we sometimes oversimplify the scientific method

18. Objectives
SPI 3210 Inq.1 Select a description or scenario that reevaluates and/or extends a scientific finding.
SPI 3210 Inq.2 Analyze the components of a properly designed scientific investigation.
SPI 3210 Inq.5 Defend a conclusion based on scientific evidence.

19. Setting Up a Controlled Experiment
Variables - factors in an experiment that can change
equipment used, type of material, amount of material, temperature, light, and time
Only one variable tested at a time
All other variables are kept unchanged, or controlled.
controlled experiment.

20. Types of variables Independent variable Manipulated variable
What you change
Dependent variable
Responding variable
Changes in response to manipulated variable
What you measure

21. Example experiment
Determining the source of life

23. Publishing and Repeating Investigations
Needham’s Test of Redi’s Findings
mid-1700s, John Needham, an English scientist
attacked Redi’s work
claimed spontaneous generation could occur under right conditions
heated gravy

24. Publishing and Repeating Investigations
Spallanzani’s Test of Redi’s Findings
Lazzaro Spallanzani, Italian
Broth had not been boiled long enough
Boiled a container of broth in a water bath for 45 minutes
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25. Publishing and Repeating Investigations
Pasteur’s Test of Spontaneous Generation
In 1864, French scientist, Louis Pasteur
designed a flask with long curved neck
showed all living things come from other living things
Image from:

26. Verifiable
What does this word mean?
How does it relate to science??

27. How a Theory Develops
Hypothesis may become so well supported scientists consider it a theory.
Theories enable scientists to make accurate predictions about new situations
As new evidence is uncovered, a theory may be revised or replaced by a more useful explanation

28. Inferences
Scientists often draw inferences from data gathered during experiments.
Inference- conclusion made on the basis of facts and previous knowledge rather than on direct observations.
Unlike a hypothesis, an inference is not directly testable.

29. Objectives
SPI 3210 Inq.1 Select a description or scenario that reevaluates and/or extends a scientific finding.
SPI 3210 Inq.2 Analyze the components of a properly designed scientific investigation.
SPI 3210 Inq.5 Defend a conclusion based on scientific evidence.

30. Precision and Accuracy
Describes the unit you used to measure
The smaller the unit of measurement, the more precise the measurement
Accuracy
How close the measurement is to the actual value
How different your number is from the accepted value

31. Qualitative vs. quantitative
Descriptive data
Quantitative
Measurement data