Scientific Method (Inquiry)
What is the scientific method…..
The scientific method is a process
______
for answering questions.
What is Science?
or
Here are a few statements
to test your current
understanding of science!
Science can prove anything,
solve any problem or answer any
question.
True or False?
False
Science actually attempts to disprove ideas (hypotheses).
Science is limited strictly to solving problems about the physical and natural world.
Any study done carefully and based
on observation is scientific.
False
Science must follow certain rules. The rules of science
make the scientific process as OBJECTIVE as is
possible.
Objective = Not influenced by feelings,
interests and prejudices; UNBIASED
vs.
Subjective = Influenced by feelings, interests
and prejudices; BIASED
Different scientists may get different
solutions to the same problem.
Understanding
Experimental Design
A process of discovery…
The Controversy Over Spontaneous Generation
Question:
What causes tiny living things to appear in decaying broth?
Needham’s Hypothesis: Spontaneous generation-Life forms arose from non-living matter.
Spallazani’s Hypothesis:
Needham
Microbes come from the air. Boiling the broth will kill them.
John
Needham
Open flask >
Spallazani
Closed flask >
1700’s
Lazzaro
Spallanzani
Louis Pastuer
…disproved the idea of spontaneous
generation of life.
Louis Pasteur
ended the
debate with his
famous swanneck flask
experiment,
which allowed
air to contact the
broth. Microbes
present in the
dust were not
able to navigate
the winding
bends in the
neck of the flask.
1800’s
Controlled all of the variables in the experiment--- GOOD EXPERIMENTAL DESIGN
Soooo…what is good science?
Objectivity is the key to good science.
and following standard procedures.
Designing Experiments
Problem: Small Pox an infections disease of humans.
•
•
Infected human population dating from 10,000 B.C.E.
The disease killed an estimated 400,000 Europeans annually during the late
of the 18th century.
•
Those infected, 20–60%—and over 80% of infected children—died from the
disease.
•
Smallpox was responsible for an estimated 300–500 million deaths during
.
Solution: ????
the 20th century
The Beginnings of Immunology
--using the scientific method
Edward Jenner and the first vaccine:
Dr. Jenner was aware of farm
workers' belief that if you had
cowpox in the past, you
wouldn’t get smallpox.
COWPOX : Infectious disease that
caused mild discomfort, aching, a few
pustules, some swelling…symptoms
that disappeared in a few days.
SMALLPOX: Infectious disease that
caused massive disfigurement,
sometimes blindness, and often death.
FYI- Last known case of Small Pox 1977.
The Beginnings of Immunology
Edward Jenner and the first vaccine.
Question: Does having cowpox make a person immune to smallpox?
Hypothesis: If someone is infected with cowpox, then they will be
immune to smallpox because having cowpox keeps a person from
getting smallpox.
Experiment: Jenner made small incisions or punctures in arms of
human subjects and rubbed in cowpox material (pus) in order to infect
them with cowpox.
Analysis & Conclusion: He saw--- that people he had infected with
cow pox, when later exposed to smallpox, would get a little bit sick,
but never come down with a full-blown case of smallpox. Cowpox
infection prevents smallpox infection.
Present Results / Peer Evaluation:At first his peers doubted the safety
and value of his treatment, but eventually the importance of the
cowpox inoculum was recognized.
1800’s – English physician
Vaccination was not without its critics. In this cartoon from 1802, the British
satirist James Gillray implied that vaccination caused people
to become part cow.
SCIENTIFIC METHOD
• A series of steps that scientists use to
answer questions and solve problems.
• Is not a rigid procedure.
• Scientists may use all of the steps or just
some of the steps.
• They may even repeat some of the steps.
• The goal of the scientific method is to
come up with reliable answers and
solutions to questions.
Scientific Method (Inquiry)
Publish
Conclusion
Observation,
Question or
Problem
Research
Hypothesis
Results
Data/Analysis
Experiment/Test
Purpose:
Observations/ Questions
• The scientific method
starts with questions
about something that is
observed. (5 Senses)
• How, What, When, Who,
Which, Why, or Where?
• Initial observations and
inferences.
Research
• Collect and
analyze
information to
increase your
understanding of a
topic or issue
(question).
Hypothesis
• A testable explanation for an answer
to an observation, question or problem.
If _ [I do this]__ then _[this]__ will
happen___because_[why]__.
Experiment/Test
• A procedure to test the
hypothesis.
• An experimenter changes one
factor and observes or
measures what happens.
Variables (Factors)
• The factor that is changed
by the experimenter is
known as the independent
variable. ( I Do.)
• The factor that is measured
or observed is called the
dependent variable. (data)
A good or “valid” experiment will only
have ONE independent variable!
Constants
• The experimenter makes a special
effort to control all the factors in an
experiment so that they will not effect
the outcome. (false results)
• These factors are called or
constants.
• Controls groups are sometimes used
to help validate an experiment. All
variables the same except for the
independent variable (IDV)
 Controls are NOT being TESTED
 Controls are also used for COMPARISON
Materials/Procedures
• Listed---Specific
detail of all of the
equipment
necessary to
complete the
experiment.
• Numbered steps
with specific details.
Results or Data-Analysis
Data: Information or observations
collected during an experiment.
Qualitative=descriptions
Quantitative=measurements
Analysis- Data is evaluated.
Look for trends
Look at all data together.
Tables and graphs are often used
to organize and analyze the data.
Conclusion
Discussion and summary
of the experiment-based
on the analysis of the
data.
Do the results support the
hypothesis?
• Discuss possible errors
• Investigate again?
• Make a new hypothesis
Publish
• Results are verified by
independent
duplication and
publication in a peerreviewed journal
•
•
Independent duplication = Two or more
scientists from different institutions
investigate the same question separately
and get similar results.
Peer-reviewed journal. = A journal that
publishes articles only after they have been
checked for quality by several expert,
objective scientists from different
institutions.
Scientific Theory vs. Law
Scientific Theory vs. Law
THEORY
Explanation for an observation or
phenomena that is confirmed by a
large amount of evidence or tests
(experiments).
Example:
Germ theory of disease - Infectious diseases result from the action
of microorganisms.
Treponema pallidum ♪ (Trep-o-neemah pal-lid-um)
LAW
A statement of a scientific principle
that appears to be without exception
at the time it is made, and always
works the same way under the
same conditions; A scientific rule.
Example:
Newton's First Law of Motion (Law of Inertia) - every object either
remains at rest or in continuous motion with constant speed unless
acted upon by an outside force.
So, what's the difference?
A SCIENTIFIC THEORY
- are typically non-mathematical.
A SCIENTIFIC LAW
- are often mathematically defined
•
Looking at things this way helps to explain, in part, why physics and
chemistry have lots of "laws" whereas biology has few laws (and more
theories).
•
In biology, it is very difficult to describe all the complexities of life with
"simple" (relatively speaking!) mathematical terms.