the scientific method mr. knowles anatomy and physiology liberty senior high school
TRANSCRIPT
The Scientific Method
Mr. Knowles
Anatomy and Physiology
Liberty Senior High School
Early Anatomists• Hippocrates- Greek
philosopher and physician, 400 B.C.
• Hippocratic Oath
• Four “Humours” of the body.
• Observations, little Experimentation
Greek and Roman Surgical Instruments
Early Black Bag
Claudius Galenus (Galen)• Roman anatomist
during the 1st Century.
• Described the human anatomy in detail.
• Little understanding of physiology.
Galen’s Office
Galen’s Specimens
Vesalius• 16th Century anatomist
who provided exquisite detail of systems.
• Experimentation with domestic animals. To determine function.
• Assumed Galen to be correct; not questioned.
Vesalius at Work!
William Harvey• 17th Century English
anatomist who questioned some of Galen’s conclusions.
• Determined how the CV system worked in 1628 publication.
• Used experimentation to prove CV function.
The Scientific Method
An empirical way of explaining phenomena in
the world.
With what does all good science research begin?
A Question!
21 Questions to Conclusions!
Make a Concept Map to Relate the Following Terms
• Theory
• Hypothesis
• Principle
• Law
See My Concept Map
Click to View
Some Definitions• Law or Fact- a confirmed observation
(direct/or indirect).• Hypothesis- a testable prediction,
based on prior knowledge and experience.
• Theory- a unifying explanation of several facts; a working model.
• Principle- who knows?
Based on our discussion…
What would you call the idea of Spontaneous
Generation?
Germ Theory?
The Role of Hypotheses in Inquiry
• In science, a hypothesis–Is a tentative answer to a well-framed
question, an explanation on trial–Makes predictions that can be tested
Hypothesis• Comes from an observation --->
question or a problem.
• It is a Testable Prediction (Maybe True or False).
• Written as an If __I.V.___, then _D.V.____ statement.
Hypotheses in Everyday Problems
Observations
Questions
Hypothesis # 1:Dead batteries
Hypothesis # 2:Burnt-out bulb
Prediction:Replacing batterieswill fix problem
Prediction:Replacing bulbwill fix problem
Test prediction
Test does not falsify hypothesis
Test prediction
Test falsifies hypothesisFigure 1.25
Deduction: The “If…then” Logic of Hypothesis-Based Science
• In deductive reasoning:
–The logic flows from the general to the specific.
• If a hypothesis is correct:
–Then we can expect a particular outcome.
Hypothetico-Deductive Reasoning
• Actually written as If… and …then…therefore.
• If …(your hypothesis)… and (planned experiment)…, then… (expected results)…therefore…(conclusion).
Hypothesis must be...• Testable (Falsifiable) (ex.
Absolute Zero---> Molecular Motion Stops)
• Unbiased (ex. Cancer statistics in North America; Utah vs, D.C.)
• Repeatable (ex. Cold Fusion, University of Utah experiment)
Pons and Fleischmann, University of Utah, 1989
An Unbiased Hypothesis?
• Research testing the hypothesis that cell phones--> brain tumors.
• Who funds this work?
• Motorola- the number one manufacturer of cell phones in U.S.
Writing a Hypothesis
Dangerous Breast Implants?
• Do breast implants cause connective tissue disease?
• How would you write a hypothesis?
What’s wrong with this?
The Scientific Method
Designing Controlled Experiments
• Experiments must be designed to test:
–The effect of one variable by testing control groups and experimental groups in a way that cancels the effects of unwanted variables.
• In mimicry– A harmless species resembles a harmful species
Flower fly(non-stinging)
Honeybee (stinging)Figure 1.26
A Case Study in Scientific Inquiry: Investigating Mimicry in Snake
Populations
• In this case study
– Mimicry in king snakes is examined
– The hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present
Scarlet king snake
Scarlet king snake
Key
Range of scarlet king snake
Range of eastern color snake
Eastern coral snake
NorthCarolina
SouthCarolina
Figure 1.27
Field Experiments with Artificial Snakes
• To test this mimicry hypothesis– Researchers made hundreds of artificial snakes, an experimental
group resembling king snakes and a control group of plain brown snakes
(a) Artificial king snake
(b) Brown artificial snake that has been attackedFigure 1.28
• After a given period of time– The researchers collected data that fit a key prediction
Figure 1.29
In areas where coral snakes were present, most attacks were onbrown artificial snakes
Key
% of attacks on artificial king snakes
% of attacks on brown artificial snakes
Field site with artificial snakes
17%
83%
NorthCarolina
SouthCarolina
XX
XX X
XX
X XX
XXXX
In areas where coral snakeswere absent, most attacks
were on artificial king snakes
84%
16%
Key
If a hypothesis meets all criteria, then...
• Test hypothesis by experimentation.
• After repeated testing, a hypothesis may support a Scientific Theory.
A Theory must ...
• Describe a real phenomenon (always true).
• Make accurate predictions about the world.
• Be dynamic, able to be refined or updated.
Model Building in Science• Models of ideas, structures, and processes
– Help us understand scientific phenomena and make predictions
To lungs To body
Rightartium
Rightartium
Rightventricle
Right ventricle
Fromlungs
Frombody
Figure 1.30
What is the difference between a fact and a theory?
• The Theory of Gravity:
Ex. Newton and Einstein- both contributed to the theory.
new information--->revision of theory.
Scientific Method• Problem
• Hypothesis
• Materials
• Procedure
1. Number steps
2. Control Group/Experimental group
3. Constants
• Data/Results
1. Title
2. Label axis: x-axis - IV
y-axis - DV
• Conclusions
(including discussion of errors)