Obj 2.1.1: List and describe the steps of the experimental method.
1 Describe the steps of the
experimental method. SR1
a] Make observations, measurements, or calculations to gather information.
b] Use these observations to form a hypothesis, and make a prediction based on
the hypothesis.
c] Conduct an experiment to test the hypothesis under controlled conditions.
d] Organize and analyze information, or data, that is gathered from the
experiment.
e] Use the data to form conclusions about the original hypothesis.
f] Repeat the experiment and share the results.
2 Describe, diagram and label the scientific method.
The scientific method is self correcting in nature:
a] Make observations and collect data that lead to a question
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b] Formulate a hypotheses & prediction----<---------+
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c] Experiment to test hypothesis |
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d] Organize and analyze the results. |
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e] State Conclusions |
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f] Hypothesis ------Contradicted----->--------------+
Confirmed
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g] Law after others also confirm it.
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h] Formulate a Theory
3 Name four ways to make an observation.
a] Using your senses of sight, smell, or hearing.
b] Instruments attached to robots or satellites.
Ex: Predicting flooding from melting snow is helped by satellite photographs of
the snow cover in the mountains.
Ex: Tracking devices attached to animals.
c] Historical records.
d] Calculations.
4 Distinguish between observation and measurement.
An observation is obtained by using our senses with or without an
instrument. A measurement is an observation that has a number assigned to it.
5 a] Define hypothesis showing a usable format.
A prediction in the form of “If X then Y.”
b] State an example.
If you double the pressure on a gas then its volume will half.
6 a] Define law. b] Name & State a law verbally
A relationship between 2 measurements w/o an explanation.
Boyle’s Law: The volume of a confined gas is inversely proportional to the
applied pressure.
7 Define theory and name two.
a] A theory is an explanation based on well-tested hypotheses about aspects
of the natural world.
b] Well known theories are
Biology--Cell Theory, Evolution
Chemistry--Atomic Theory, Kinetic Theory of Gasses.
Geology--Plate Tectonics
Physics--Gravity, Relativity
c] A theory has the following properties:
i] It attempts to explain the relationship between two events.
ii] It makes predictions.
iii] It is testable, it can be proven wrong.
d] A theory is not a conjecture, opinion, speculation or hypothesis.
e] A theory does not have to be consistent with all known facts.
Ex: light travels in straight lines.
8 a] How does a hypothesis become a law?
If after being tested many times the hypothesis is not proven wrong it is
accepted as a law.
b] How does a hypothesis become a theory?
A hypothesis is part of the scientific method but cannot become a theory by
itself because it is not an explanation
9 Explain the following:
a] "There are two possible outcomes:
If the result confirms the hypothesis, then you've made a measurement.
If the result is contrary to the hypothesis, then you've made a
discovery." Enrico Fermi
If the hypothesis is confirmed the experiment tells you something you already
knew.
If the hypothesis is contradicted the experiment tells you must rethink your
analysis and learn something new.
b] "No amount of experimentation can ever prove me right; a single experiment
can prove me wrong." Albert Einstein
The defining characteristic of a scientific theory is that it makes
falsifiable or testable predictions.
10 State the four rules of experimental design.
a] All variables must be measurable.
b] Change one variable at a time.
c] Use a control condition.
d] Write the procedure in enough detail so the experiment can be reproduced.
Obj 2.1.2: Describe why a good hypothesis is not simply a guess.
11 a] Explain why a hypothesis is not just a
guess. SR3
i] A hypothesis considers information gained by observation of other people
while a guess might not.
ii] A hypothesis is testable while a guess might not be.
b] A hypothesis is called an educated guess.
What qualifies a guess as “educated”?
To be educated the guess has to be based on all the previously known
evidence and not just the personal experience of the experimenter.
12 What can you change if you want to repeat an
experiment to test a hypothesis?
You have two options: change nothing and you will prove your measurements
are reliable. Or change a minor detail that will help generalize the
hypothesis. Ex: If your hypothesis is about the effect of vitamins on the
growth of bacteria change the strain of bacteria.
Obj 2.1.3: Describe the two essential parts of a good experiment.
13 Describe the two essential
parts of a good experiment, and explain their importance. SR5
The two essential parts of a good experiment are testing one variable at a
time and using a control condition.
Testing one variable at a time is important to be sure that this variable alone
is the cause of the effect.
Often in an experiment there are many variables that can effect an outcome.
Using a control condition can eliminate many alternate explanations of
experimental results.
Obj 2.1.4: Describe how scientists study subjects in which
experiments are not possible.
14 List four situations (2 from
the text) where scientists try to answer questions that cannot be tested with
experiments.
a] Studying magma chambers inside a volcano.
b] Studying the sun’s interior.
c] Studying the source of cholera.
d] Studying why the early settlements disappeared.
15 Explain how scientists try to answer questions that
cannot be tested with experiments. Define terms. SR4
Scientists study correlations, reliable associations between two events, to
answer questions that cannot be investigated with experiments. The more
correlations that exist between variables, the more sure scientists can be of
their conclusions.
16 How did drawing a map of London help John Snow solve
the cholera problem in 1854? RCpg39
His map was effectively a correlation between the distance from various water
wells and the homes of those stricken with cholera. The solution was to close
the wells with the most cholera cases near them--the Broad Street well.
Obj 2.1.5: Explain the importance of curiosity and imagination in
science
17 Name three scientific habits of
mind and explain their importance. SR2
a] Curiosity leads scientists to ask new questions.
b] Skepticism leads scientists to question explanations they doubt.
c] Openness to new ideas prevents scientists from limiting their thinking.
d] Intellectual honesty helps insure accurate conclusions.
e] Imagination and creativity help scientist conceive new instruments,
measurement techniques, and explanations.
18 What habits of mind must a scientist have that relates
to the first step of the scientific method?
The first step of the scientific method is to ask a question. This requires
curiosity and creativity to ask a new question or skepticism to question an
explanation they doubt.
19 How can a scientist be both skeptical and open to new
ideas at the same time? Describe such a situation. SR6
a] Skepticism about established ideas allows a scientist to be open to new
ones.
b] Ex: Galileo’s disbelief in Aristotle’s assertion that heavier objects fall
faster.
Back to the Top
Obj 2.2.1: Explain how scientists use statistics.
1 a] What does the text mean by the population of dwarf
wedge mussels?
A population is a group and not a number.
It means all the dwarf wedge mussels in the river.
b] What are the symbols for population mean and standard deviation?
Population mean: μ; standard deviation: σ
c] What are the symbols and equations for the sample mean and standard
deviation?
_ _______________
Sample Mean = X = ΣXi/N; Sample STDEV = √Σ(Xi-Xavg)2/N-1
2 a] How scientists use statistics to summarize,
characterize, analyze, and compare data. (4 examples)
Characterizing Data:
The mean and standard deviation are used to characterize data.
Summarizing Data: Bar graphs, pie charts
Comparing:
Scientists will test hypothesis by comparing the means and standard deviations
of different populations.
b] State an example of how they compare data.
Hypothesis may be that the mean weight of the GHS girls is 130 lb.
They will use one class as the sample and find the sample mean and standard
deviation. If 130 is more than 1 standard deviations from the sample mean we
will reject the hypothesis.
3 a] A class is made of 3 boys, each with an IQ of 70,
and 6 girls, each with an IQ of 130.
i] What is the equation for the class average IQ?
ii] Find the average IQ for the class.
Avg IQ = NbxIQb + NgxIQg = 3x80 + 6x120 = 110
Nb + Ng 3 + 6
iii] What is the equation for the class IQ standard deviation?
Define terms.
_____________________
s = √{Σ[n(Xi
- Xavg)2]/N-1}
N = Total number of subjects = 3 + 6 = 9
n = Number of subjects in each category.
s = Standard Deviation of the sample.
iv] Find the class IQ standard deviation.
____________________ ____________________________
s = √Σ[n(Xi
- Xavg)2]/N-1 = √{[3(80
- 107)2+6(120-107)2]/8} = 20 mm
b] Find the mean length of the dwarf wedge mussel population. RCpg41
Length (mm)| 15 | 20 | 25 | 30 | 35 | 40 | 45 |
Number | 2 | 4 | 16 | 22 | 9 | 5 | 3 | Total = 61
L x Number | 30 | 80 |400 |660 |315 |200 |135 | Total = 1820
Avg Length = 1820/61 = 30 mm
c] What is the probability that a mussel is 30 mm long?
22/61 = 36%
4 a] Define: mean, mode, and median, distribution.
Mean: The expected value of a randomly variable, i.e., a randomly
chosen subject. It is obtained by adding up the data for a given characteristic
and dividing this sum by the number of individuals.
Mode: The category with the most number of score in it.
Median: The score with 50% of the population below & 50% above it.
Distribution: A list, ordered by quantity, showing the number of times
each value appears. It can be represented by a bar graph and used to calculate
probabilities.
c] Draw the diagrams for 3 types of distributions, label (5) one.
Skewed left, Skewed right, & Symmetric, Probability, Measurement, X1, X2,
Area = Probability Measurement Lies between X1 and X2
5 a] Have each person at your table throw a die six
times and record the number of times a one showed up.
You will get one number for each person present, up to a max of 4.
The numbers will range from zero to ten.
b] Ask a neighboring table for their numbers.
c] Record all 8 numbers in a table.
d] Plot it, and determine the mode.
e] Determine its mean
f] What type of distribution is it?
6 a] Define correlation.
Correlation is a linear relationship between two variables.
b] Draw and label the diagram for a correlation.
c] State two ways this graph can be interpreted.
i] If you increase X (Democratic Party Registration) you will increase Y
(Cancer incidents)
ii] If you increase Y (Cancer incidents) you will increase X (Democratic Party
Registration)
d] How are correlations used?
Correlations are used to support a hypothesis in situations were
direct experiments are not possible.
e] What caution applies to correlation studies?
Correlations do not show cause and effect.
State an example of this.
There is a positive correlation between the rise in the Democratic
Party and the rise in cancer.
f] A correlation is a form of circumstantial evidence.
g] It takes 3 correlation(s) to prove a hypothesis.
7 a] Show the calculations for the mean and standard
deviation of the following data: Weight (lb)| 92 | 105 | 110 | 125 | 130|
Mean = (92+105+110+125+130)/5 = 112
Std= √[(92-112)2 + (105-112)2 + (110-112)2 +
(125-112)2 + (130-112)2]/4
= √[202 + 72 + 22 + 132 + 182]/4
= √[400+49+4+169+324]/4 = √946/4 = 15 lb
b] Draw and label (3 words, 6 numbers) a diagram showing how to test a
hypothesis that that population average is 130 lb.
c] State your assumption.
d] For the hypothesis to be true it would have to lie between
X - s and X + s+ 112-15 and 112+15 = 98 & 127 lb
Obj 2.2.2: Explain why the size of a statistical sample is important.
8 Explain why sample size is important in determining
probability. SR1
The sample needs to be large enough to reflect the population.
If it is not large enough it can easily misrepresent probabilities.
9 Explain what “the mean number of weeds in three plots
of land” means.
The statement means that someone has determined how many weeds are in each of
three plots, added these numbers together, and divided by three.
SR2
Obj 2.2.3: Describe three types of models commonly used by
scientists.
10 a] Describe 4 types of models commonly used by
scientists. SR3
b] Name some examples of each.
Physical models are three dimensional and closely resemble the object
or system they represent.
Ex: Models of a plant cell, DNA, or a building.
Graphical models, which include maps and charts, illustrate data such as
positions or amounts graphically.
Ex: Maps that show the position of stars, the amount of forest cover in a given
area, the depth of water along a river.
Conceptual models show how something works or how it is organized.
They can be both conceptual and physical.
Ex: A flow chart of a computer program.
Ex: A chart of how mercury moves through the environment.
Ex: Model of the atom.
Mathematical models use one or more equations to represent how a system
or process works.
Ex: The law of gravity: Fg = GM1M2/d2
c] Draw the conceptual model of mercury contamination.--pg 45
Mercury released from burning coal
\|/
+------Air------+
Soil<---------->Water
Crops Fish
+--->People<----+
\|/
Health effects from mercury poising.
11 How does building a conceptual model help scientists
in their work?
A conceptual model helps scientists to understand a system by showing what
components the system contains, how they are arranged, and how they affect one
another.
Obj 2.2.4: Explain the relationship between probability and risk.
12 Explain the relationship between probability and
risk. SR4
Probability is the chance that an event will occur.
Risk is the probability of an unwanted outcome.
Obj 2.2.5: Explain the importance of conceptual and mathematical
models.
13 Why are conceptual and mathematical models especially
powerful? SR6
Mathematical models have the potential of making very accurate predictions.
Conceptual models can communicate how complex systems work.
Back to the Top
An Environmental Decision-Making Model, pg 47
Obj 2.3.1: Describe three values that people consider when making
decisions about the environment.
1 List and define three pairs of competing values to
consider when making environmental decisions.
SR2
Environmental values are based on how important nature and the environment
are to you.
Ex: Habitat preservation.
Ex: Preventing species from extinction.
Ex: Maintaining water and air quality.
Ex: Preventing ocean level rise.
Economic values are based on monetary costs and benefits.
Ex: Return for paying taxes on vacant property.
Ex: Return for property taken over by the government.
Ex: Invest for retirement.
Ex: The price, in dollars, for a property.
Recreational values are based on the importance of leisure and having fun.
Short term economic values often compete with environmental and recreational
values.
Long term economic values support and do not compete with environmental values.
2 a] Write down a problem in your life that presented a
difficult decision.
b] How did you approach the decision? Was it by flipping a coin, talking to
your friends, or a third way?
3 NIMBY, which stands for Not In
My Backyard, refers to the reaction many people have
towards something they consider unpleasant being located near their homes.
NIMBY may apply to things that are dangerous, unsightly, noisy, or inconvenient.
State two examples of what might elicit an NIMBY response.
a] Airports benefit the economy as a whole but no one wants it.
b] Wind farms often elicit a NIMBY reaction.
c] Foxwoods Casino Philadelphia, on a 16.5-acre vacant parcel east of
Christopher Columbus Boulevard between Tasker and Reed streets.
Obj 2.3.2: Describe the four steps in a simple environmental decision
making model.
4 Why is a decision-making model helpful for making
environmental decisions? RC, pg
47
A decision making model is helpful for making environmental decisions because
it provides a systematic way of analyzing the issues and determining what is
important.
5 Diagram a simple decision making model. (Fig 16)
Gather -------->Consider --->Explore-------->Make a
Information Values Consequences Decision.
6 Explain the importance of each of the four steps in a
simple decision-making model.
SR1
Gathering Information is important to fully understand a problem.
Considering Values is necessary to so that a decision is made based on
what is important to the decision-maker.
Exploring Consequences is important because it is necessary to consider
the long-term impact of a decision.
Making a Decision is important so that something can be done to implement
the decision maker’s values.
7 Set up a 12 cell decision making table.
Table 4, pg 50
|<-----------------Values---------------->|
Consequences | Environmental | Economic | Recreational |
----------------------------------------------------------------
Positive Short-term | | | |
----------------------------------------------------------------
Negative Short-Term | | | |
----------------------------------------------------------------
Positive Long-term | | | |
----------------------------------------------------------------
Negative Long-term | | | |
----------------------------------------------------------------
A Hypothetical Situation, pg 48
Obj 2.3.3: Compare the short-term and long-term consequences of two
decisions regarding a hypothetical environmental issue.
*8 a] Describe the decision-making process for the
Everglades example.
Gathering Information: Biologists documented the pollution and the
decline in the number and size of mangrove islands, the number of species, fish,
bird, and wildlife populations.
Economists identified $200 million loss in fish and wildfowl.
City governments documented the size and location of human population that
depended on the everglades for drinking water.
The negative impact on the tourism and farming industries was also documented.
Considering Values: mitigate flooding, conserve water, preserve fish &
wildlife, and make land available for development.
Exploring Consequences: Failure to return the flow of water into the
everglades spelt disaster for the south Florida economy.
Making a Decision: It took 5 years for committees to form, learn to trust each
other, and craft a plan. They decided to capture the “fresh water that now
flows unused to the ocean and the gulf and redirect it to areas that need it
most. The majority of the water will be devoted to environmental restoration,
reviving a dying ecosystem. The remaining water will benefit cities and farmers
by enhancing water supplies for the south Florida economy.”
http://www.evergladesplan.org/about/about_cerp_brief.aspx
b] Explain why it is so difficult for people to agree on how to restore the
Everglades. Case Study, pg 49
People are motivated by different values and interests. Even when different
groups could agree that action head to be taken, they argued on the scope and
methods of restoration.
c] If your county decided to build a landfill, do you think the
decision-making process would resemble the Everglades Example.
Democratic community decisions occur when people with different values come
to an agreement and establish trust.
9 There are both emotional arguments and factual
arguments.
a] List three emotional statements and three factual statements.
b] State an example of an emotional argument.
c] State an example of a factual argument.
d] Which argument should have the most weight?
How to Use the Decision-Making Model, pg 50
10 a] Describe two examples of situations in which
environmental values come into conflict with other
values. SR3
b] Make a decision-making table that shows the positive and negative
consequences of two possible decisions. SR4
11 Suggest how to make the decision-making model
presented here more powerful.
SR5
Quantify the positive and negative consequences to better asses the
situations.
Back to the Top
Conservation Status
Law Prediction
Correlation
Mean Probability
Data Measurement Risk
Decision-Making Table Model Sample
Distribution Model, Conceptual Spread
Distribution, Normal Model, Decision-Making Standard Deviation
Endangered Model, Graphical Statistics
Experiment Model, Mathematical Theory
Group, Control Model, Physical Threatened
Group, Experimental NIMBY Value
Habitat Observation Variable
Hypothesis Population Wind Farm
Hypothesis, Null
Conservation Status: An indicator of the likelihood of
that species remaining extant either in the present day or the near future.
There are three categories.
Correlation: The linear dependence between two variables.
Data: Any pieces of information acquired through
observation or experiment.
Decision-Making Table: A graphic organizer that has
Short-term & Long term, Positive & Negative Consequences for the environmental,
economic, and recreational aspects for a plan of action.
Distribution: the relative arrangement of the members of a
statistical population, usually shown in a graph.
A list, ordered by quantity, showing the number of times each value appears. It
can be represented by a bar graph.
Ex: Normal Distribution
http://www.shodor.org/interactivate/activities/NormalDistribution/?version=1.6.0_07&browser=Mozilla&vendor
Endangered: At risk of extinction.
Experiment: A procedure that is carried out under
controlled conditions to discover, demonstrate, or test a fact, theory ,or
general truth.
Group, Control: A group that serves as a standard of
comparison with another group
Group , Experimental: A group that is identical to a
control group except for one factor and that is compared with the control group.
Habitat: The specific environment in which an organism
lives.
Hypothesis:
a] A testable idea or explanation that leads to scientific investigation.
b] A prediction in the form of “If X then Y.”
Hypothesis, Null: There is no difference between the
experimental and control groups.
Law: A relationship between two events without an
explanation.
Ex: Boyl’s Law: The volume of a confined gas is inversely proportional to the
pressure (V = k/p)
Mean: The number obtained by adding up the data for a
given characteristic and dividing this sum by the number of individuals.
Measurement: An observation that has a number assigned to
it.
Model: A pattern, plan, representation, or description
designed to show the structure or workings of an object, system or concept.
A representation of some properties of a device, system or object.
Model, Conceptual: A verbal or graphical explanation for
how a system works or is organized.
Model, Decision-Making: a conceptual model that provides a
systematic process for making decisions.
Model, Mathematical: one or more equations that represents
the way a system or process works.
Model, Physical: A three dimensional constructions that
resembles the object or system they represent.
Ex: An architect’s three dimensional model of a building.
Normal Distribution: A bar graph of the data takes the
shape of a bell, with the data grouped symmetrically around the mean.
NIMBY: Not In My Backyard
The reaction many people have towards something they consider unpleasant being
located near their homes.
Observation: The process of obtaining information by using
the senses; the information obtained by using the senses.
Population: A set of entities with specific
characteristics that is under study.
A group and not a number.
All girls between 14 and 18 years of age.
All the dwarf mussels in a river.
All the plants of a certain species.
Prediction: A statement made in advance that expresses the
results that will be obtained from testing a hypothesis if the hypothesis is
supported.
Probability:
a] The likelihood that a possible future event will occur in any given instance
of the event.
b] The ratio of the number of times one outcome of any event is likely to occur
to the number of possible outcomes of the event.
Risk: The probability of an unwanted outcome.
Sample: The group of individuals or events selected to
represent a statistical population.
Spread: The range of numbers in a measurement or
calculation.
Ex: Range = Max - Min,
Standard Deviation:
A measure of the dispersion of a frequency distribution.
√Σ(X-Xavg)2/N
The average distance between data points and the average of all the data.
Statistics: The collection, analysis, interpretation, and
presentation of masses of numerical data.
Theory: A synthesis of a large body of information that
encompasses well-tested and verified hypotheses about aspects of the natural
world.
Threatened: Likely to become endangered.
Value: A principle or standard that an individual
considers to be important.
Variable: A factor that changes in an experiment in order
to test a hypothesis.
Wind Farm: A group of wind turbans connected to the
electrical grid.
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