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SCIENCE
Definition of Science
A way of exploring and explaining the natural world
Using a process designed to reduce the chance of being misled
Scientific disciplines
Branches of scientific knowledge that are limited in size and scope to make them more manageable.
In reality, all branches of scientific knowledge are inter-related and dependent on each other
Can you name some scientific disciplines?
Scientific disciplines
All scientific disciplines are either:
1. Physical Science: study of matter and energy Astronomy, geology, physics, and
chemistry
2. Biological Science: study of living organisms Botany (plants) or Zoology (animals)
See figure 1.1 in your book
Chemistry is a scientific discipline
Concerned with the composition, structure and properties of matter, as well as the changes it undergoes during chemical reactions
Incorporates concepts of energy in relation to chemical processes
Chemistry is a scientific discipline
It is fundamental to an understanding of all processes of the living state Biochemistry: the study of the
chemical processes of living organisms
Chemistry is a scientific discipline
Chemical processes produce the products needed for our clothes, housing, transportation, medications and recreational pursuits
Scientific disciplines
The knowledge in separate scientific disciplines combined create the whole of scientific knowledge currently known.
For example, knowledge of how the human body works requires knowledge in the areas of biology, chemistry, and physics.
Can you think of some examples?
SCIENTIFIC METHOD:
PART I:
The process of science!!
The Scientific Method Make observations Ask questions Develop a hypothesis Make predictions Test the predictions
Experiment Manipulate variables
Independent Dependent
Conclusions: analyze and interpret results
Peer Review/Publication The “scientific method” is a
formalized version of the procedure any of us might take, using common sense, to resolve a problem.
(Withgott and Brennan, 2007)
1. OBSERVATION
The light doesn’t turn on
2. QUESTION
Why didn’t the light turn on?
3. MULTIPLE HYPOTHESES
What are all the possible answers
(hypotheses) to the question?
Example: The light bulb is burned out
Example 2: ?
4. PREDICTIONS
What data would support a particular hypothesis (= expected
data) and/or what data would refute the hypothesis?
Example: The light bulb will rattle when shaken
5. TESTS (Experiments)Conduct tests to collect actual
data?
Example: Shake the light bulb and record sound
6. TENTATIVE CONCLUSIONS
Which hypotheses were supported (not refuted) by the actual data?
Write up report (introduction, methods, results, discussion) for
publication
7. PEER REVIEW & PUBLICATIONSubmit your report to a scientific journal that is
peer-reviewed, meaning that your methods, data, tentative conclusions will be scrutinized by
scientists whose reputation is at stake if they allow your report to be published.
Publication leads to creation of scientific information
The Scientific Method Scientific
understanding advances through evaluation and dissemination of information to the scientific community.
How does this information get disseminated to the public?
(Withgott and Brennan, 2007)
THE NATURE OF SCIENTIFIC PROOF & KNOWLEDGE
PART II:
Nature of scientific proof
Hypothesis: A possible explanation or statement that might be
true and will be tested by the scientific method. Can be falsified Cannot be positively proven Therefore, hypothesis are accepted not proven
Nature of scientific proof
Example: Observation: All the swans you have ever seen
are white Hypothesis: All swans are white Test: examine large number of swans Tentative conclusion: all swans are white
(hypothesis accepted) If you looked at a million white swans, there
could still be a black one However, if you found just one black swan,
your hypothesis would be falsified
Nature of scientific proof
When a hypothesis withstands RIGOROUS testing, especially over time, it becomes a theory
Theory: A hypothesis that has been rigorously tested and
over time has become generally accepted by the scientific community as correct
Nature of Scientific Proof
Some examples of theories are: Theory of relativity Theory of plate tectonics Theory of evolution
Eventually theories become laws Law of gravity
Nature of Scientific Knowledge
The main body of science is very stable and grows by being corrected slowly
So, although scientists accept that scientific knowledge is always open to improvement, the main body of knowledge is well-accepted and stable
Nature of Scientific Knowledge
Scientific fact A valid observation about some natural
phenomenon obtained by carrying out experiments
Scientific theory: A hypothesis that has been tested and validated
over a long period of time Theory of evolution
Nature of Scientific Knowledge
Scientific law: generalization that summarizes facts about natural phenomena Law of gravity
Scientific law vs scientific theory: Law addresses how it behaves Theory addresses why it behaves that way
Scientific Worldview There are several beliefs underlying the
work of scientists: By working together over time, people can
figure out how the world works Knowledge is both stable and changing
Scientists become excited by new ideas, but are skeptics that judge ideas by the strength of the evidence that supports them.
Scientific Worldview
The universe is a unified system functions in accordance with fixed natural laws that do not
change from time to time or from place to place Knowledge gained from studying one part of it can often be
applied to other parts of it
All events arise from some cause or causes and, in turn, cause other events.
We can use our senses and reasoning abilities to detect and describe natural laws that underlie the cause and effect relationships we observe in nature.
Are the terms Science and Technologysynonymous?
Science Technology Technology = the application of scientific knowledge for practical purposes.
EXPERIMENTAL DESIGN
PART III:
Experiments--definition A well-defined, controlled procedure for
obtaining information about a system under study
A way to test an hypothesis
Experiments—some rules
1. Adequate Sample Size. Ex. Larger sample size better
2. Representative Sample. Ex. Random sample
Manipulative or controlled study Uses a model system to control and manipulate variables An experiment in which variables are taken into account Based on comparing a control group with an experimental
group Both groups are treated identically except for one variable or
factor This factor is changed for the experimental group but not the
control group If an effect is seen in the experimental group but not the
control group that indicates that the factor changed is the cause of the effect
Examples of Controlled Studies
Studying the effect of nutrients on plant growth—add or change the kinds & amounts of nutrients in natural or artificial setting
Studying the effect of grazing on plant communities—exclude grazing on study plots & allow grazing on others
Challenge: hard to do over large scales of space & time
Controlled study
Variables: factors that affect observations or experiments Dependent variable—response that is
measured Independent variable—varied or manipulated
by researcher (cause)
AN EXAMPLE OF A CONTROLLED STUDY
THE MEALWORM MYSTERY
MEALWORM MYSTERY
A student conducted 4 experiments to determine how mealworms respond to light and moisture.
All variables except light and moisture were held constant from experiment to experiment.
For each experiment, 12 mealworms were placed in the center of a box and then their positions were recorded 24 hours later.
EXPERIMENT 1
QUESTION: Are mealworms attracted to light?
mealworm
QUESTION 2: Are mealworms affected by moisture?
Answer? You can’t tell; it could be either or both
EXPERIMENT 2
QUESTION: Are mealworms affected by light?
QUESTION 2: Are mealworms affected by moisture?
Answers?
They are affected by light; we don’t know about moisture
EXPERIMENT 3
QUESTION: Are mealworms affected by light?
QUESTION 2: Are mealworms affected by moisture?
Answers?
With just this experiment, it seems they didn’t move
EXPERIMENT 3
QUESTION: Are mealworms affected by light?
QUESTION 2: Are mealworms affected by moisture?
Using the information from the other 2 experiments…
Answers?
Yes and Yes (despite attraction to light, they avoided wet
THE EXPERIMENTS1 2
3
QUESTION: Which variables affect mealworm movement based on the above experiments (note that movement may be either toward or away from something)? A. Light but not moisture. B. Moisture but not light. C. Both light and moisture. D. Neither light nor moisture. E. Can’t tell.
mealworm
Without the controlled experiment we would know nothing!