Transcript Ch 2 notes powerpoint

Chapter 2
•Tools of
environmental
science
Introduction
• How is thinking
scientifically similar
to how you usually
think about things?
• What values do
people consider when
making a decision
about the
environment?
Chapter 2 Section 1
• Objectives:
• 1. What is meant by the experimental
method?
• 2. Define hypothesis.
• 3. Explain why a good hypothesis is not
simply a guess.
• 4. Why do scientists write predictions?
• 5. Name the two essential parts of a
good experiment.
• 6. What is the difference
between the experimental
group and the control group in
an experiment?
• 7. Define variable.
• 8. What is the purpose of the
control in an experiment?
• 9. Describe how scientists
study subjects in which
experiments are not possible.
• 10. Why is it important that scientists
repeat their experiments?
• 11. Explain the importance of curiosity
and imagination in science.
The experimental method
• Define the problem
• Collect information on the problem
(observe)
• Form a hypothesis; make a prediction
• Conduct an experiment to test the
hypothesis
• Record data from the experiment
• State a conclusion
• Communicate the results
Controlled experiment
• Involves two groups, the
control group and the
experimental group
• Involves a control, the
standard for comparison
• Involves a variable, the one
condition being changed in the
experiment
Variables
• Independent Variable
• The one factor that is
manipulated by the
scientist
• It causes the change
in the dependent
variable
• Dependent variable
• The change that
occurs because of the
independent variable
• Smithers thinks that a special juice will
increase the productivity of workers. He
creates two groups of 50 workers each and
assigns each group the same task (in this
case, they're supposed to staple a set of
papers). Group A is given the special juice
to drink while they work. Group B is not
given the special juice. After an hour,
Smithers counts how many stacks of
papers each group has made. Group A
made 1,587 stacks, Group B made 2,113
stacks.
The correlation method
• Used when questions cannot
be answered by
experimentation
• Does not necessarily prove
cause-and-effect relationships
between two variables
• Not reliable
Scientific habits of mind
• Curiosity
• The habit of skepticism
• Openness to new ideas
• Intellectual honesty
• Imagination and creativity
Chapter 2 section 2 objectives
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Objectives:
1. Define statistics.
2. Explain how scientists use statistics.
3. Explain why sample size is important in
determining probability.
• 4. What is mean?
• 5. List four types of models commonly used
by scientists.
• 6. Explain the relationship between
probability and risk.
How scientists use statistics
• Scientists rely on statistics to
summarize, characterize, analyze, and
compare data.
• Scientists uses statistics to describe
statistical populations.
• A statistical population is a group of
similar things that a scientist is
interested in learning about.
What is the Average?
• Although statistical populations are composed
of similar individuals, these individuals often
have different characteristics.
• For example, in the population of students in
this classroom, each student has a different
height, weight, and so on.
• The mean is the number obtained by adding
up the data for a given characteristic and
dividing this sum by the number of
individuals. Another term for mean is
average.
Distribution Curve
• The relative arrangement of the
members of a statical population
• A normal distribution forms a bellshaped curve around the mean
What is Probability?
• The chance that
something will
happen (like
flipping a coin)
• Often determined
by observing
ratios or patterns
Models
• Physical
• Graphical
• Conceptual
• Mathematical
Chapter 2 - Section 3
• Objectives:
• 1. Define value.
• 2. List and define three values that people
consider when making decisions about the
environment.
• 3. List the four steps in a simple
environmental decision-making model.
• 4. Describe in a short paragraph examples of
two situations in which environmental
values come into conflict with other values.
Ch 2 Section 3
Values and the Environment
• Values are principles or
standards that an individual
considers to be important.
An Environmental DecisionMaking Model
• A decision-making model is a
conceptual model that provides
a systematic process for
making decisions.
Decision-Making Model
A Hypothetical Situation
• The golden-cheeked warbler population is
declining in Valley County.
• The town of Pleasanton, in Valley County, is
growing rapidly, and much of the new
development is occurring outside the city limits.
• Biologists who have been studying the warbler
warn county officials that if they do not take
action, the state fish and wildlife service may list
the bird as an endangered species.
• Several groups join together to propose
that the county buy several hundred acres
of land where the birds are known to breed
and save the land as a nature preserve.
• The group also proposes limiting
development on land surrounding the
preserve.
• The group obtains enough petitions to put
the issue to a vote, and the public begins to
discuss the proposal.
• People who own property within the
proposed preserve oppose the plan.
• These property owners have an economic
interest in the situation. They believe that
they will lose money if they are forced to
sell their land to the county instead of
developing it.
• Other residents do not like the idea of more
government regulations on how private
property can be used.
• Other landowners support the plan and fear
that without the preserve the warbler will
be listed as an endangered species. Once
listed as endangered, the state will impose
a plan to protect the bird that will require
even stricter limits on land development.
• People who have land near the preserve
think that their land will increase in value.
• Many residents also look forward to hiking
and camping in the preserve.
How to Use the DecisionMaking Model
• The hypothetical situation in Pleasanton
can be used to illustrate how to use the
decision-making model.
• Michael Price is a voter in Valley County
who will vote on whether the county
should create the nature preserve.
• The steps Michael took to make his
decision follow.
Gather Information
• Michael studied the warbler issue
thoroughly by watching local news reports,
reading the newspaper, learning more
about the golden-cheeked warblers from
various Websites, and attended forums
where the issue was discussed.
• Several of the arguments on both sides
made sense to him.
Gather information
• Michael also gathered
scientific information
that included graphs
of the decline of the
warbler population.
Consider Values
• Michael made a table to help him clarify
his thoughts and values.
• Michael considered the environmental,
economic, and recreational values of the
preserve.
• He believed these to be important, but
someone else might have thought other
values were more important to consider.
Should the Valley County Set
Aside a Nature Preserve?
Explore consequences
• Michael decides that in the short term, the
positive and negative consequences listed in his
table were almost equally balanced.
• For example, some people would suffer
financially from the plan, but others would
benefit.
• Also, taxpayers would have to pay for the
preserve, yet all residents would have access the
previously private property.
Explore consequences
• It was the long term consequences that allowed
Michael to make his decision.
• Michael realized that the environmental values
were an important factor in his decision.
• The thought of the warbler becoming extinct
distressed him, and protecting the habitat now
would be less costly that protecting it later under
a state imposed plan.
Explore consequences
• Michael considered that there were long
term benefits as well.
• He had read that property values were
rising rapidly in counties where land was
preserved for recreation.
• He also found that people would pay more
to live in counties that have open spaces.
Explore consequences
• Because the county contained little
preserved land, Michael thought that
creating the preserve would bring the
county long-term economic benefits.
• He also highly valued the aesthetic and
recreational benefits of the preserve, such
as walking trails.
Make a Decision
• Michael chose to vote in favor of the
nature preserve.
• However, someone else who looked at the
same table of pros and cons might have
voted differently.
• If you lived in Valley County, how would
you have voted