What is Science

1
What is Science?

• Some big concepts about how science works

2
What is science?

• An organized body of knowledge about nature
• A method of exploring nature and the order within
  it
• A tool for answering questions about the physical
  world

3
What is science?

• Scientists deal with natural phenomena (events)
  which can be observed, measured, and tested by
  scientific methods
• Scientific study is based upon the assumption
  that the universe is orderly, reasonable, and
  testable.
• Science does not have the answers to all of the
  questions in the universe, or the solutions to
  all human problems.

4
Why do science?

• To explore new phenomena
• Check previous results
• Test theoretical predictions
• Compare different theories to see which is better

5
Science or Pseudoscience?

• Pseudoscience is literally fake science
• Think about the following
• evidence (data)
• reproducibility
• successes and failures
• peer review

6
Why is belief in pseudoscience so strong?

• Ignorance
• Superstition
• Coincidence
• Newspapers and magazines
• What do you see?
• Daily science column or daily horoscope column?
• Television
• The era of sell-TV and paid infomercials
• Diets, Vitamins, Muscles, Cleaning Supplies

7
High Dollar Pseudoscience Astrology

• 20,000 Astrologers
• Millions who pay for readings
• Nancy Reagan used an astrologer to help determine
  Ronald Reagans calendar
• A greater percentage of Americans believe in
  astrology and occult phenomena TODAY than in
  medieval Europe

8
What is technology?

• Application of science
• Focuses on ways to use scientific knowledge to
  solve problems or help people
• Example
• Science What are the properties of
  semiconductors?
• Technology How can semiconductors be used to
  create logic chips for computers and cell phones?

9
How are science and technology related?

• Scientific discoveries can lead to the
  development of new technologies
• e.g. Discovery of x-rays lead to medical
  applications of x-rays to look at bone fractures
• New technology can lead to scientific discoveries
• e.g. Ability to form beams of x-rays and
  sensitive detectors lead to discovery of x-ray
  diffraction which tells us about the structure of
  crystals

10
How do scientists pick what to work on?

• Societal needs
• Whats hot in the scientific literature
• What new techniques are available
• What methods are likely to be fruitful
• What you can get funding for

11
The Scientific Method

• A logical, stepwise way to solve problems
• There are different traditions in science about
  what is investigated and how
• E.g. plant research vs. geology
• All have in common certain basic beliefs about
  the value of evidence, logic, and good arguments.

12
The Scientific Method

• Observe the physical world
• Identify a question or problem
• Create a hypothesis (educated guess) to answer
  the question
• Predict observable consequences
• Test the predictions with a well-designed
  experiment
• Draw a conclusion
• Revise if necessary and go back
• Replicate/verify
• Communicate the results

Galileo 1564-1642
http//antwrp.gsfc.nasa.gov/apod/image/0110/galile
o_sustermans_big.jpg
Sir Francis Bacon 1561-1626
http//www.batesville.k12.in.us/Physics/PhyNet/Abo
utScience/Inductive.html
13
The Scientific Method

• Is based on the principle of cause and effect
• Is a dynamic process
• Not a strict series of ordered steps
• You often need to go back to an earlier step
  based on new information you discover
• Some of the greatest discoveries come from
  observations that prove the initial hypothesis
  WRONG

14
The Scientific Method
15
A Scientific Hypothesis

• Is an educated guess
• Can be wrong
• Must be testable or capable of being proven wrong
• Principle of falsifiability

• No number of experiments can prove me right a
  single experiment can prove me wrong. --Albert
  Einstein

http//www.grafologiamorettiana.it/apropositodi/Ei
nstein.htm
16
Is it a scientific hypothesis?

• Paris Hilton is the best looking woman in the
  world
• Intelligent life exists on planets somewhere in
  the universe besides earth
• The moon is made of Swiss cheese
• Better stock market decisions are made when
  Venus, Earth and Mars are aligned
• Atoms are the smallest particles of matter that
  exist
• Outer space contains a kind of matter whose
  existence cant be detected or tested
• Albert Einstein was the greatest physicist of the
  20th century

17
How does having a hypothesis help?

• Helps you choose what data is important
• Helps you choose what additional data is needed
• Helps you interpret your results

18
Designing a Good Experiment

• Define your problem clearly
• Research what is already known to help you decide
  on your hypothesis
• You do not have to reinvent the wheel!
• Write down a testable scientific hypothesis

19
Designing a Good Experiment

• Define your variables (what is changing in the
  experiment)
• Independent variables are
• things you can control (knobs!)
• Causes
• Go on the x-axis in a graph
• Dependent variables are
• things that are changed during the experiment
  (observables)
• Effects
• Go on the y-axis in a graph

20
Designing a Good Experiment

• Change only one independent variable at a time!
• Controlled Variables
• All the other independent variables you could
  change if you wanted to but keep fixed for this
  particular experimental run
• Have a control
• A set of conditions where nothing is supposed to
  happen according to your hypothesis
• Usually at the lowest or highest value of the
  independent variable you are changing
• A point of comparison

21
What if you cant control the variables?

• Examples
• Study of weather, climate, volcanoes, stars (not
  practical)
• Progress of disease (not ethical to give people a
  disease)
• Answer
• observe as wide a range of natural occurrences as
  possible to be able to discern patterns

22
Designing a Good Experiment

• What do you expect your data to look like if the
  hypothesis
• is true?
• is false?
• How are you going to analyze your data and
  display it to make the observations and
  interpretation clear?
• What are your critical assumptions?
• What is the range of applicability of your
  conclusions?

23
Bias

• Your are more likely to notice examples that fit
  your theory than examples that dont
• To avoid bias you can use observers who dont
  know what the results are supposed to be (blind
  tests)
• Bias may not be avoidable, but scientists want to
  know possible sources and effects

24
Some More Vocabulary

• Facts
• Something competent observers can observe and
  agree to be true
• Laws or Principles
• Scientific hypothesis that has been tested many
  times and never contradicted
• Theory
• Combination of facts and well tested hypotheses
  that provide the best current explanation of all
  observations
• Can be proved wrong by new observations

25
What Laws do you know?

• Law of Conservation of Mass
• Law of Conservation of Energy
• Emc2

26
What is a theory?

• A valid scientific theory offers a well-defined
  naturally occurring cause (mechanism) which
  explains why or how a natural event (phenomenon)
  occurs.
• Scientific theories are always subject to change
  (tentative, uncertain).

27
Thinking about theories

• With your partner open your envelope marked 1
  and arrange the pieces of the puzzle to make a
  simple shape
• When you have your square, open the envelope
  marked 2 and make a new simple shape
• How is the puzzle like scientific theories?

28
Thinking about theories
29
Theories Change!

• Short run
• New theories that dont mesh with current
  understanding often get criticized
• Long run
• Theories are judged by
• how they fit with other theories,
• the range of observations they explain,
• how well they explain observations,
• how effective they are in predicting new
  findings.
• No matter how well one theory fits observations,
  a new theory might fit them just as well or
  better, or might fit a wider range of
  observations

30
Theories Change!

• Testing, changing, modifying and discarding
  theories never ends
• Usually changes are smallmodifications
• Sometimes there are dramatic changes
• We get a better understanding but
• We NEVER get to absolute truth

31
How is a Law Different from a Theory?

• Laws summarize what will happen
• For every action there is an equal and opposite
  reaction
• Often expressed as an equation
• Fma
• Theories explain how or why something happens