Transcript Questions for Today

Questions for Today
1. What is the Nature of Science?
2. What are the differences between a theory and
a law?
3. What are the differences between inductive and
deductive reasoning?
4. What are the two categories that Scientific
Results fall into?
5. What are the limitations of Environmental
Science?
What is the Nature of Science?
• Science is an attempt to discover order in
the natural world and to use that knowledge
to make predictions about what is likely to
happen in nature.
What is the Nature of Science?
• There are no set steps in understanding nature.
Scientists often follow a method in developing scientific
explanations, though not in not always in the order listed:
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Ask a Question or identify a problem.
Collect data by making observations and measurements.
Develop a hypothesis
Make Predictions
Test Predictions
Accept or reject the hypothesis
• The purpose of Science is to explain natural phenomena
with scientific theories.
Differences between Theory and
Law.
• A widely tested and accepted scientific
hypothesis becomes a scientific theory.
– Before becoming a theory, the data from the
hypothesis must pass peer review, skepticism,
and must be reproducible.
– Examples of Scientific Theories are Evolution,
the Atomic Theory, and Schrödinger’s Cat.
Schrödinger’s Cat
Differences between Theory and
Law.
• A scientific law describes what we find
happening in nature over and over again.
– Examples of Scientific Law are the Laws of
Thermodynamics, Law of Gravity, and
Newton’s Laws.
Inductive vs. Deductive
Reasoning
• Scientists use inductive reasoning to
convert observations and measurements to
a general conclusion and deductive
reasoning to convert a generalization to a
specific conclusion.
Inductive vs. Deductive
Reasoning
• Inductive reasoning uses specific observations and
measurements to derive a hypothesis or conclusions
– “Bottom-up” reasoning
– From the very specific to the general
– Experimental Scientists
• Deductive reasoning uses logic to arrive at a specific
conclusion based on a generalization or premise.
– “Top-down” reasoning
– From generalizations to a specific conclusion
– Sherlock Holmes
Inductive Riddle
• You have two fuses of equal length and are
made from the same material.
• You know that the fuse burns for one hour,
but burns for different rates.
• How would you measure 45 minutes?
Deductive Riddle
• Somewhat ate the butcher’s
sausages!
• Here are what the four boys at
the scene of the crime said:
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A: “B ate the sausages!”
B: “D ate the sausages!”
C: “I didn’t eat them, no way!”
D: “B is totally lying!”
• Only one of these boys are
telling the truth, and all the
others are lying. Who is telling
the truth and who ate the
sausages?
What are the two categories
that scientific results fall into?
• Scientific results fall into two categories:
those that have not been confirmed
(frontier science) and those that have been
well tested and widely accepted (sound or
reliable science).
What are the two categories
that scientific results fall into?
• Frontier science is results that are often
controversial because they have not been
widely tested and accepted by peer review.
What are the two categories
that scientific results fall into?
• Sound science, also called consensus science,
consists of data, theories, and laws that are
widely accepted by scientists who are considered
experts in the field.
– Check the U.S. National Academy of Sciences and the
British Royal Society.
– Junk (unreliable) Science are scientific results or
theories that are presented as sound science, but have
not undergone rigorous peer review or have already
been discredited by peer review.
What are the limitations of
Environmental Sciences?
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Scientists can disprove things but cannot prove
anything absolutely because there is always some
degree of uncertainty in scientific findings.
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Scientists try to establish high probability (90-99%) in their
findings.
I.E. Scientists rarely say that “Cigarettes cause lung cancer,”
they might say, “Overwhelming evidence from thousands of
studies indicates that there is a significant relationship between
cigarette smoking and lung cancer.”
Scientists are human and cannot be expected to be
totally free of bias about their results.
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What are the limitations of
Environmental Sciences?
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Another limitation in Environmental Science is
the validity of the data.
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No way to measure some of the statistics due to size
and time
Use Statistical Samples and Models
They predict trends
Most environmental problems are difficult to
understand because they involve many
variables and highly complex interactions.
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What are the different factors that lead to the
depletion of species?