Transcript science - CDS 130

Lecture 2: The Scientific
Method
What is Science?
What is Science?
a) the state of knowing : knowledge as distinguished from
ignorance or misunderstanding
b) a: a department of systematized knowledge as an object
of study <the science of theology> b: something (as a
sport or technique) that may be studied or learned like
systematized knowledge <have it down to a science>
c) 3 a: knowledge or a system of knowledge covering
general truths or the operation of general laws especially
as obtained and tested through scientific method
b: such knowledge or such a system of knowledge
concerned with the physical world and its phenomena
: natural science
d) 4: a system or method reconciling practical ends with
scientific laws <cooking is both a science and an art>
http://www.merriam-webster.com/dictionary/science
The Scientific Method
the process
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characterization of existing data
formulation of a hypothesis
deduction - formulation of a predictive test
experimental testing
error elimination and characterization
validate or revise hypothesis
How to evaluate a report on a
scientific work
• What are the assumptions?
– Are they consistent with the conclusions?
• What is the data set?
– How many trials?
– Is the data public?
• Was the result peer reviewed?
– By whom?
– Has it been cited?
• Is the claim falsifiable?
– Are there enough details to reproduce the result?
Values and Science
is science good or bad?
• GOOD Science Things
– Medicine and longer Life Spans
– Better Transportation
– Spam, Tang, and Artificial Food Products
• BAD Science Things
– Atomic Bombs
– Telephones and Computers
– Spam, Tang, and Artificial Food Products
Is science good?
• Science is a process to investigate ideas
• There are Ethical issues in the science
process
– Human Subject and Animal Research
– Bioethics and Medical Ethics
– Scientific Integrity and Fraud
• Science is a tool that can be used ethically
and unethically
• Science is NOT Technology
Random Data
image one
Random Data
image two
Combined
True random data has unusual clusters and patterns
What is Science?
In-class problem 1
• Suppose each student in class flips a coin
and they all end up heads. Can we
conclude that the coins are fair? What
would happen if we repeated this
experiment 100 times and every time the
same number of students got heads and
the same number tails?
Pseudo-Sciences
• Astrology
• UFOs
• Cold Fusion
Astrology
very old ideas
“THAT a certain power, derived from the ethereal
nature, is diffused over and pervades the whole
atmosphere of the earth, is clearly evident to all men.
Fire and air, the first of the sublunary elements, are
encompassed and altered by the motions of the ¾ther.
These elements in their turn encompass all inferior
matter, and vary it as they themselves are varied;
acting on earth and water, on plants and animals.”
Ptolomy, Tetrabiblos 2nd Century AD (translated by
J.M. Ashmand 1822)
Astrology
a short history
• Celestial motions were used to measure time
• It was clear that the things in the sky influenced
Earth
– Planting and harvesting of crops were associated with
which stars were in the sky
– Seasonal changes, including the flooding of the Nile,
was predicted from the stars
– The position of the Moon clearly was related to tides
• Perhaps the positions of the planets affected the
fates of Kingdoms and Kings
Modern Astrology
• Sun Sign Astrology
– Related to the position of the Sun along the
Zodiac at your time of Birth
– Twelve different constellations that have been
associated with personal characteristics
• Sun Sign Astrology can be tested
Typical Sun Sign Horoscopes
Sagittarius November 22 - December 21
For Monday, January 21 -Are you hungry for a new
adventure? Of course you are! There is so much in life to
discover, and today is just as good as any other day to
start exploring! Travel is a great idea right now -especially travel to a foreign country. Get online and start
planning your next trip. If you don't have the time or the
finances for such an elaborate expedition, then just grab
some friends and check out a restaurant that serves food
from a country you'd like to visit. Feed your wanderlust
with food.
© Astrology.com 1996-2008
Typical Sun Sign Horoscopes
Capricorn December 22 - January 19
For Monday, January 21 -It won't be easy to get alone
time today -- your presence will be much in demand from
two different groups. So if you are craving some solo
hours, you could be facing a tough challenge. If you can,
just give in and get together with the people who are
clamoring for your attention. There will be plenty of time
in the coming days to go off on your own and think or
relax. For now, you will need to try to find happiness in
the energy generated when you're in the midst of people.
© Astrology.com 1996-2008
Typical Sun Sign Characteristics
Sagittarians
... have a positive outlook on life, are full of enterprise, energy,
versatility, adventurousness and eagerness to extend experience
beyond the physically familiar. They enjoy travelling and exploration,
the more so because their minds are constantly open to new
dimensions of thought. They are basically ambitious and optimistic,
and continue to be so even when their hopes are dashed. Their
strongly idealistic natures can also suffer many disappointments
without being affected. They are honorable, honest, trustworthy,
truthful, generous and sincere, with a passion for justice. They are
usually on the side of the underdog in society they will fight for any
cause they believe to be just, and are prepared to be rebellious.
They balance loyalty with independence.
2008 - Astrology.com
by Pamela McHenry, "StarGoddess"
Typical Sun Sign Characteristics
Sagittarians
... have a positive outlook on life, are full of enterprise, energy,
versatility, adventurousness and eagerness to extend experience
beyond the physically familiar. They enjoy travelling and exploration,
the more so because their minds are constantly open to new
dimensions of thought. They are basically ambitious and optimistic,
and continue to be so even when their hopes are dashed. Their
strongly idealistic natures can also suffer many disappointments
without being affected. They are honorable, honest, trustworthy,
truthful, generous and sincere, with a passion for justice. They are
usually on the side of the underdog in society they will fight for any
cause they believe to be just, and are prepared to be rebellious.
They balance loyalty with independence.
2008 - Astrology.com
by Pamela McHenry, "StarGoddess"
Typical Sun Sign Characteristics
Aquarians
...basically possess strong and attractive personalities. They fall into
two principle types: one shy, sensitive, gentle and patient; the other
exuberant, lively and exhibitionist, sometimes hiding the
considerable depths of their character under a cloak of frivolity. Both
types are strong willed and forceful in their different ways and have
strong convictions, though as they seek truth above all things, they
are usually honest enough to change their opinions, however firmly
held, if evidence comes to light which persuades them that they
have been mistaken. They have a breadth of vision that brings
diverse factors into a whole, and can see both sides of an argument
without shilly-shallying as to which side to take. Consequently they
are unprejudiced and tolerant of other points of view. ...
2008 - Astrology.com
by Pamela McHenry, "StarGoddess"
Testing Sun Sign Astrology
• Hypothesis: The zodiacal sign you are born
under influences your career, health, and life
• Deduction: Certain objective elements, such as
career, disease and personality should be
correlated with when you are born
• Experiment: Study the careers, health, and
personality types of people and see if they
depend on birthday
Sun Sign Results
• There is no correlation between Birthday
and career, health, and personality as
measured in objective large studies
• Numerous studies show the same results
• There is no evidence that Sun Sign
Astrology works
Astrology
how to write a good horoscope
• Be Vague
– ``Changes are happening in your life''
• Be Double-Headed
– ``You have sound judgement, but sometimes make
terrible mistakes''
• Be Modal
– ``At times, you find people very difficult''
• Be Favorable
– ``Your intelligence can often be misunderstood by
others"
Perception and Science
• Humans are excellent at finding patterns, even
when there aren't any
• It is very easy to let subjective perception
overwhelm objective tests
• We need to make specific predictions before the
experiment takes place
• We need to test the predictions using statistics
Other Sciences
from The USA Today,
Jan 15, 2008
Existing Evidence
Hypothesis
Extended Hypothesis
Two Big Rules in Science
• The Burden of Proof is on the person
MAKING the CLAIM.
• EXTRAORDINARY CLAIMS DEMAND
EXTRAORDINARY PROOF
The Science Debate
• Every day, people are debating scientific
issues
• Most scientific debates have two sides
– Majority opinion
– Minority opinion
Scientific Opinions
• Opinions held by Scientists in the Field
• Opinions held by the General Public
• Do opinions matter in science?
How do we resolve scientific
disagreements?
• EVIDENCE and DATA
– How was the experiment done?
– Was it repeated by others?
– Is the new theory TESTABLE?
Warning Signs in Public Debates
• Beware Citations to Authority
– DATA is important, not words.
• Beware of Minority Opinion
– Why don't most scientists believe it?
• Beware Magicians choice
– Attacks where the other is weakest
Beware the Underdog Syndrome
• Everyone loves an underdog.
– Everyone thought Galileo was wrong.
– Everyone thinks I am wrong.
– Galileo was right.
– I might be right too.
http://www.alleenschule.teck.de/schueler/hotpot-h1-h5/cloze/under%20the%20table.jpg
Science and the media
• What role does the media play in science
stories?
Science and the media
• The media reports new things - hence the name
"news"
• New ideas in science are often released before
peer review through press releases
• According to one study, about half of press
releases in science end up being wrong!
• That's why we need peer review!
Science and the media
• The media cares about interesting stories stories that are exciting, new and controversial
• All sources are ``equal'' in many science stories
• Not everyone on all sides of a debate have
equal credibility
• Not all stories have equal credibility, and some
with little credibility are very interesting
Cold Fusion
Cold Fusion
all Physics Labs Try to Recreate the Experiment
• Measurements taken off Television
• Hundreds of Experiments begin with in
days
Cold Fusion
initial results
• Some other labs detect Fusion
• Most other labs detect nothing?
• Utah creates ``Cold Fusion Institute''
• Multimillion dollar project
Cold Fusion
what happened?
• Errors were found in poorly designed
experiments
• There was no PEER REVIEW of the
original results
• Original Results were Release in a Press
Conference, not a Journal
Scientific Publications and Peer Review
the publication process
• A Scientist comes up with a new result
• A Paper is written and submitted to a Journal
• The Editor gives it to one or more anonymous reviewers
who provides feedback about the paper and the science
• Basically, there are three possible results from the
reviewer
– This is perfect! Publish it NOW!
– This is crap! Don't publish it in this journal - EVER!
– This is OK, but it needs some work. I want to see revisions.
• This gets more complicated when there are multiple
reviewers
Scientific Publications and Peer Review
the publication process - revision
• The author gets the results, and usually makes
revisions
• After the reviewer and author finish the revision
cycle, the paper is put into proof form
• Final edits are made... and
• The paper is published
Scientific Publications and Peer Review
the publication process – published papers
• Once the paper has been published, other scientists
read it
• If the paper is relevant to their work, the paper is cited in
other papers written by other scientitst
• The impact of the paper is often judged by its number of
Citations
• Different scientific fields have different standards
• In astronomy, a transformational paper could have
thousands of citations
The broader impact of publications
future directions in Science
• Publications and their impact are often used to judge the
importance of scientific work
• The previous work helps determine the funding for
projects
– Science agencies have review panels, but previous work is an
important consideration in judging proposals
– Science funding can be extremely competitive
– Success rates are typically between 5\% and 25\% in most
programs
• Funding helps determine the future direction of research
• So... peer reviewed publications drive science
The bottom line
• Peer review in Science is essential!
• Objective testing and unbiased review
help keep scientific progress on track