Introduction to Experimental Science
Mrs. Donna Leonardi
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Scientists
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More than anything else, scientists are
skeptical.
Most (not all) scientists do research to
gather data to prove or disprove
hypotheses.
Scientists practice Discovery Science
and/or Hypothesis Driven Science
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Research Methods
Researchers are . . .
like detectives – gather evidence,
develop a theory.
Like judges – decide if evidence meets
scientific standards.
Like juries – decide if evidence is
“beyond a reasonable doubt.”
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Science . . .
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Is cumulative. Current research builds
on previous research.
Usually Employs the Scientific
Method:
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Empirical (acquires new knowledge via direct
observation and experimentation)
Systematic, controlled observations.
Unbiased, objective.
Operational definitions.
Valid, reliable, testable, critical, skeptical.
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What is Research?
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Research is the scientists way of
producing new information.
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Clearly defined steps
Repeatable
Clear and concise communication
A search for a way to explain an observation
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Scientific Method
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Making an observation, formulating a
question, gathering background
information, constructing a hypothesis.
Creation of the Research Investigational
design, subjects, materials and
procedures
Data Collection and Analysis
Discussion and Interpretation of findings
and conclusion
Next step action plan
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Observation
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The pivotal event in research is the
observation
 Published material
 Physical event
 Trigger
 This event drives the entire focus
and direction of the investigation
 Take ownership of the investigation
which leads to more detailed
observation
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Observation
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An observation is the process of
focusing on an object, organism, or
event using one of more of your five
senses, thought, or memory, for
some unspecified amount of time
and recording some aspect of that
object or event.
The observation is stated
objectively
The observation does not include
interpretation
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Acid Rain
1959
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Make an Observation
Activity 1
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Write your name three times on a piece of
paper with a pencil.
Tightly hold several ice cubes in your
hand for one minute
At the end of one minute, immediately
throw the cubes into a beaker and write
your name three more times.
Warm your hands by rubbing them
together.
Again write your name three more times.
Make an observation and record it.
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Make an Observation
Activity 2
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Alex Rodriquez has hit 52 home runs this year and is
a strong candidate for the American League MVP.
Alex Rodriquez is a right handed batter.
Jorge Posada is also a candidate for American
League MVP.
Jorge Posada is a switch hitter and has 19 home
runs.
In the top 20 hitters in career batting average, there
are no switch-hitters. Two switch-hitters reside on
the lists of most career base hits. In career home
runs, Mickey Mantle is the top switch-hitter at No.
13. Mantle is the only switch-hitter in the top 20 in
career home run percentage.
Make and observation and record it.
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Make an Observation
Activity 3
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The Erlenmeyer flask in front of you was
filled with nutrient broth and subsequently
autoclaved.
The flask was placed into the refrigerator
over the summer.
The organism growing in the flask appears
to be bread mold, Rhizopus stolonifer .
There appears to be a centrally located focus
in the spherical formations of mold in the
flask.
To the best of my knowledge, the flask was
never opened after being autoclaved.
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Objective Observation
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Stated in the form of a declarative
sentence
Stated in a clear and detailed
manner, limiting it to a single
element or event as much as
possible
The sensory experiences should be
recorded or documented as
accurately as possible with no
interpretation
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Objective Observation
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Pure reflection of what is
experienced
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Taste (gustatory)
Auditory
Olfactory
Touch (Haptic)
Visual
Does not include any feelings or
thoughts about what you sensed
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Subjective Observation
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Avoid subjective observations
 Interpretations thoughts and feelings about
what you experienced through your senses.
 Subjective or objective????
 Electrical impulses coming from the
electric eel speed up when the lights are
turned off.
 Electric impulses coming from the electric
eel speed up greatly when the lights are
turned off.
 Rewrite you observation from the ice cube
experiment or the batting observation.
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Background Information Activity 2
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In baseball, a switch-hitter is a batter who is able
to hit from both the right and left sides of the plate.
Right-handed batters have a higher batting average
against left-handed pitchers and vice-versa
Players learn to switch-hit.
Reaction time (RT) is the elapsed time between
the presentation of a sensory stimulus and the
subsequent behavioral response.
http://biae.clemson.edu/bpc/bp/Lab/110/reaction
.htm
Continued…..
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J Am Optom Assoc. 1997 Jan;68(1):439.
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Association between visual reaction time and batting, fielding, and
earned run averages among players of the Southern Baseball
League.
Classé JG, Semes LP, Daum KM, Nowakowski R, Alexander LJ,
Wisniewski J, Beisel JA, Mann K, Rutstein R, Smith M, Bartolucci A.
School of Optometry, University of Alabama at Birmingham 35294, USA.
BACKGROUND: This study was performed to investigate the relationship
between vision reaction time (VRT) and batting, fielding, and pitching skill in
baseball. METHODS: A vision screening of 213 professional baseball players
in the Southern Baseball League was performed, and the visual reaction
times of these players were determined. Official Southern Baseball League
statistics were consulted to obtain the players' batting average, fielding
average, and earned run average. RESULTS: The mean visual reaction time
for all players was 239 msec. There was no significant association between
mean VRT and age or race. The mean VRT for dominant eyes was not
significantly different from the mean VRT for nondominant eyes. For the 92
players who batted at least 100 times, an association was found between
mean VRT and batting average (p = 0.017). For the 168 fielders in the
league playing at least 20 games, no statistically significant association was
found between mean VRT and fielding average. Similarly, no association was
found between mean VRT and earned run average for the B8 pitchers who
had participated in more than 20 games. CONCLUSIONS: An association was
found between visual reaction time and batting skill in baseball. No
association was found between visual reaction time and fielding or pitching
skill.
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A hypothesis to explain the observation
From Activity 2
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There is a statistically significant
difference between reaction time when a
switch hitter bats from the right or the
left side of the plate.
There is a statistically significant
difference between the reaction time of
the right and left hand.
Your Hypotheses
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The Experiment for Activity 2
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Reaction Time Calculation
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The Experimental Plan
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We have made a pivotal observation that switch
hitters hit fewer homeruns than non switch hitters.
Background research has led me to the idea that
reaction time affects batting success (J Am Optom
Assoc. 1997 Jan;68(1):43-9).
Background research has also led me to the idea
that reaction time may differ between the right and
left hand, and that this is the reason switch hitters
hit statistically fewer homeruns and have a lower
batting average than non switch hitters.
In my background research, I have never checked to
see if switch hitters have developed faster reaction
times than the general population with their non
dominant hand, if, indeed, there is a difference in
reaction time between the dominant and non
dominant hands. .
In my background research, I have never checked to
see that right handed switch hitters hit more
homeruns when they are batting right handed.
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1. The first step in planning an experiment
is choosing an answerable question.
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Progress in an area is made by rejecting a
hypothesis. This is the logical experimental
framework.
There is no such thing as PROOF.
All the possible alternative explanations for
a phenomenon or all experimental outcomes
must be listed and an attempt made to
eliminate each possibility.
The most likely explanation to me is that
there is a difference in reaction time
between dominant and non dominant
hands.
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2. The second step in an experimental
design is determining what kind of data will
be needed to answer your question.
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What kind of data?
How much data? Determine appropriate
sample size.
The entire experiment should be thought
through at the start!!
All the statistical tests are merely ways to
examine different kinds of data, collected
in different ways, to determine whether
you have a statistically significant reason
to reject your Null Hypothesis.
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The Null Hypothesis
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Because the logical experimental
framework is based on the rejection
of hypotheses, experiments usually
begin with the Null Hypothesis.
The Null Hypothesis is the
hypothesis of no difference.
What is the Null Hypothesis in our
case?
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The Null Hypothesis Ho
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Ho There is no difference between
the reaction time of the dominant
and non dominant hand.
If I fail to reject the Null Hypothesis
with no significant findings, my
experiment is over.
If I fail to reject the Null Hypothesis
and have significant findings, this is
an important step forward.
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The Alternative Hypothesis Ha
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Since I am interested in showing
there is a difference, my Alternative
hypothesis would read:
There is a difference between the
reaction time of the dominant and non
dominant hand.
I have stated nothing about which hand
would have a faster reaction time.
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Alternative Answers must be listed
within the logical framework
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H1 = Reaction time in the dominant
hand is faster than reaction time in
the non dominant hand.
H2 = Reaction time in the non
dominant hand is faster than
reaction time in the dominant hand.
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A research proposal must be written at
this time
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Question being asked
Statement of the Null and Alternative Hypotheses
Justification of the effort (Why? What is the big picture?
Relevant published literature mentioned.) and expense
Experimental design including specific equipment and
techniques (Reference to previously published
procedures being followed.
Controls and variables described
Sample size
Flow chart of decision points in the experiment (If A
then B).
Statistical method being employed.
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Basic Research Proposal Format
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Title
Question
Why This Question
Experimental Logic Ho, H1, H2 etc.
Methods and Materials
Proposed Statistical Treatment
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Let’s get started!!
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Ho There is no difference between
the reaction time of the dominant
and non dominant hand
H1 = Reaction time in the dominant
hand is faster than reaction time in
the non dominant hand.
H2 = Reaction time in the non
dominant hand is faster than
reaction time in the dominant hand
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Data Collection
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Collecting reaction time data
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Reaction time t = √(2d/g)
How many pieces of data?
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What Statistical Method?
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Using the resources provided,
determine which statistical method
is most appropriate for the data?
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