1-2 scientific methodology State your question or the problem Do background Research Formulate a hypothesis, identify variables Design a Controlled Experiment, establish a procedure Record Results Analyze Results Draw a conclusion Present results

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Science as a Way of Knowing • Scientific understanding is always changing. • Good scientists are skeptics who question both existing ideas and new hypotheses.

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Science and Human Values • An understanding of science and the scientific approach is essential to making intelligent decisions. • Scientists make recommendations based on data collected through research. Slide 3 of 32

Science and Human Values • Decisions involve many factors besides scientific information, including: • • • •

the society in which we live economic considerations laws moral principles

•

Citizens decide what to do when they vote. Slide 4 of 32

Exploration and Discovery: Where Ideas Come From – Scientific is closely linked to exploration and discovery. – Scientific methodology starts with observations and questions that may be inspired by scientific attitudes, practical problems, and new technology.

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The Role of Technology – Technology, science, and society are closely linked.

Technological advances can also have big impacts on daily life. In the field of genetics and biotechnology, for instance, it is now possible to mass-produce complex substances—such as vitamins, antibiotics, and hormones—that before were only available naturally.

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Designing an Experiment – How do scientists design experiments to test hypotheses? – Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or controlled.

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Designing an Experiment – testing a hypothesis • The process of testing a hypothesis includes: –Asking a question –Forming a hypothesis –Setting up a controlled experiment –Recording and analyzing results –Drawing a conclusion Slide 8 of 32

Designing an Experiment – Asking a Question

• Many years ago, people wanted to know how living things came into existence. They asked: • How do organisms come into being?

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Forming hypotheses • For centuries, people believed that life arose from non living matter as an explanation for the sudden appearance of some organisms • Such as: maggots on meat; mice from grain; beetles from dung • Spontaneous generation, hypothesizes that life could arise from nonliving matter Slide 10 of 32

Forming a Hypothesis • One early hypothesis was spontaneous generation, or the idea that life could come from nonliving matter. For example, most people thought that maggots spontaneously appeared on meat. • In 1668, Redi proposed a different hypothesis: that maggots came from eggs that flies laid on meat.

1626 - 1697 (aged 71) Medical doctor in Florence, Italy

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Setting Up a Controlled Experiment • The variable that is deliberately changed is called the independent variable. • The variable that is observed and that changes in response to the independent variable is called the dependent variable. • Think: Independent = manipulated variable Dependent = responding variable Slide 12 of 32

Redi’s Experiment on Spontaneous Generation

Independent Variable

Dependent Variable

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Designing an ExperimentRecording and Analyzing Results

• Scientists keep written records of their observations, or data. • Sometimes drawings are used to record certain kinds of observations • Researchers use computers to record and review their work Slide 14 of 32

Designing an Experiment – Drawing a Conclusion

• Scientists use the data from an experiment to evaluate a hypothesis and draw a valid conclusion. • Redi’s results supported the hypothesis that maggots were produced by flies, not spontaneous generation. Slide 15 of 32

Repeating Investigations • Scientists repeat experiments to be sure that the results match those already obtained.

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Peer Review

– Scientists share their findings with

the scientific community by publishing articles that have undergone peer review. – In peer review, scientific papers are reviewed by anonymous, independent experts. – Reviewers read them looking for oversights, unfair influences, fraud, or mistakes in techniques or reasoning. They provide expert assessment of the work to ensure that the highest standards of quality are met.

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Repeating InvestigationsNeedham's Test of Redi's Findings – In the mid 1750’s, an Englishman named John Needham challenged Redi’s results by claiming that spontaneous generation could occur under the right conditions. – Needham sealed a bottle of gravy and heated it to kill all living things in the gravy – After several days, the gravy was swarming with microorganisms. – Needham concluded that these organisms came Slide from the gravy by spontaneous generation. 18 of 32

Repeating Investigations: Lazzaro Spallanzani's Test of Redi's Findings • Conclusion – nonliving gravy did not produce living thing. The microorganisms in the unsealed jar were off spring of microorganism that entered the jar through the air

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Pasteur's Test of Spontaneous Generation

– French scientist, Louis Pasteur conclusively disproved the hypothesis of spontaneous generation in 1864 – Prior to this, scientists continued to support the spontaneous generation hypothesis due the fact that “air” was the necessary “life force” in the process of generating life – Pasteur showed that all living things come from other living things.

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The Impact of Pasteur’s Work • Pasteur saved the French wine industry, which was troubled by unexplained souring of wine. • He saved the silk industry, which was endangered by a silkworm disease. • He began to uncover the nature of infectious diseases, showing that they were the result of microorganisms.

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When Experiments Are Not Possible • It is not always possible to do an experiment to test a hypothesis. For example: –Wild animals must be observed without disturbing them. –Ethical considerations prevent some experiments. By carefully planning alternative investigations, scientists can discover reliable patterns that add to scientific understanding. Slide 22 of 32

How a Theory Develops

–As evidence from numerous investigations builds up, a hypothesis may become so well supported that scientists consider it a theory. –In science, the word theory applies to a well-tested explanation that unifies a broad range of observations. Slide 23 of 32

How a Theory Develops • No theory is considered absolute truth. • As new evidence is uncovered, a theory may be revised or replaced by a more useful explanation.

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Scientific Attitudes –

Good scientists share scientific attitudes, or habits of mind, that lead them to exploration and discovery.

– Curiosity, skepticism, openmindedness, and creativity help scientists generate new ideas.

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Curiosity & Creativity – Often, results from previous studies also spark curiosity and lead to new questions. – Researchers need to think creatively to design experiments that yield accurate data.

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Skepticism – Good scientists are skeptics, which means that they question existing ideas and hypotheses, and they refuse to accept explanations without evidence. – Scientists who disagree with hypotheses design experiments to test them. – Supporters of hypotheses also undertake rigorous testing of their ideas to confirm them and to address any valid questions raised.

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Open-Mindedness –

Scientists must remain openminded, meaning that they are willing to accept different ideas that may not agree with their hypothesis.

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Science, Ethics, and Morality –

When scientists explain “why” something happens, their explanation involves only natural phenomena. Pure science does not include ethical or moral viewpoints.

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Biologists explain what life is and how it operates, but science cannot answer questions about why life exists or what the meaning of life is.

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Similarly, science can tell us how technology and scientific knowledge can be applied but not whether it should be applied in particular ways.

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Avoiding Bias – The way that science is applied in society can be affected by bias, which is a particular preference or point of view that is personal, rather than scientific.

– Science aims to be objective, but scientists are human, too. Sometimes scientific data can be misinterpreted or misapplied by scientists who want to prove a particular point.

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Understanding and Using Science – Scientists make recommendations about big public policy decisions, but it is the voting citizens who influence public policy by casting ballots. – In a few years, you will be able to exercise the right to vote. That’s why it is important that you understand how science works and appreciate both the power and the limitations of science.

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Science and Human Values

• “Bioethics”

study of what is right and wrong in biological information and technology

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So… • SCIENCE • Based on facts, measurements, observations, tests • ?Michael Shermer: Baloney Detection Kit?? - YouTube

• BIOETHICS • Based on opinion, right and wrong, past experiences Slide 33 of 32

1–2

In an experiment, the variable that is deliberately changed is called the

a. control. b. manipulated Independent variable. variable Dependentvariable. variable c. responding

d. constant control.

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1–2

The mistaken belief that living organisms can arise from nonliving matter is called

a. biogenesis. b. Pasteur's theory.

c. spontaneous generation. d. Spallanzani’s hypothesis.

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1–2

Which of the following was the manipulated variable in Redi’s experiment?

a. the kind of meat used b. the temperature the jars were kept at

c. the gauze covering on some jars d. the kind of fly that visited the jars

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1–2

A well-tested explanation that unifies a broad range of observations is a

a. hypothesis. b. variable.

c. control. d. theory.

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1–2

A scientific explanation does not become a theory until

a. a majority of scientists agree with it. b. it has been supported by evidence from numerous investigations and observations. c. it is first proposed as an explanation. d. it is published in a textbook.

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