Evidential Bases
Dr. Frank Jenkins
Centre for Mathematics Science
and Technology Education (CMASTE)
Secondary Education, U of A
Inquiry Based Science Education
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Evidence-Based Reasoning
There is evidence to suggest that many
undergraduate students (and the public)
who do not understand the importance
of evidence-based reasoning; e.g.,
 psychic fairs, pseudoscience, astrology
 television shows and movies
 lack of understanding of what research
is about in their field of work
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Potential Evidential Bases
1.
2.
3.
4.
5.
thought
experiment
demonstration
dry lab (lab
exercise)
wet lab (actual)
simulation/
animation
video analysis
7. video lab
8. computer
probes/sensors
9. field trip
10. remote access
6.
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1. Thought Experiment
The most famous person to use thought
experiments extensively was Albert
Einstein; e.g., concept of relativity.
 The teacher/scientist draws a diagram
(or waves her hands) and describes an
experiment that is imaginary.
 Evidence is often is the form of “If we
double this variable, what happens?”

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2. Demonstration
The teacher or a student or group of
students conduct an experiment in front
of a science class.
 Often done because of lack of
equipment for the whole class.
 Sometimes there are safety issues and
the teacher conducts the experiment.

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3. Dry Lab (Lab Exercise)
This is a pencil and paper lab
experience where parts of a lab report
are presented for students to complete.
 Often the evidence is given for analysis.
 Used for exercises, homework, and
examination questions.
 Often presented as open entry.

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4. Wet Lab (laboratory experience)
This is a hands-on individual (or small
group) student laboratory experience.
 Wet lab is a chemistry expression.
 Ideally this is the kind of lab experience
that is available to all students.
 Sometimes this experience is provided
at home or some alternative location.

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5. Field Trip (field work)
This evidence gathering experience
involves leaving the school.
 Often a nature field trip.
 Can be a trip to an alternative location
(e.g., a university) to use equipment.
 In this context the field trip must involve
gathering evidence to be analyzed.

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6. Video/Photo Lab
Evidence is presented through a video.
 Easier done with qualitative evidence.
 Can involve quantitative evidence.
 Any lab experience can be videoed.
 Some of these experiences are
available on video tape or disk.
 Some experiences are on the Internet.

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7. Computer Video Analysis
Computer programs are available that
present video from which evidence is
gathered; e.g., every fraction of a
second for the motion of an object.
 The computer program generates tables
and graphs of evidence.
 The computer program often provides
an analysis of evidence and graphing.

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8. Computer Simulations
Computer simulations or animations are
often referred to as learning objects.
 The laboratory equipment may be
animated and appear to generate table
of evidence and graphs.
 The evidence may or may not have any
measurement error programmed in.

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9. Computer Probes/Sensors
Probes are attached to a computer or
like device; e.g., temperature and pH.
 Evidence is gathered by the computer
and presented in tables and/or graphs.
 Evidence can be gathered in the field
and then transferred to a computer.
 Evidence can be gathered for 24 h+.

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10. Remote Laboratory Work
Laboratory work is conducted over the
Internet, connected to equipment.
 One is able to adjust the variables and
gather the evidence as if being there.
 An example would be to conduct an e/m
experiment by manipulating the electric
and magnet fields and measuring the
curvature of an electron beam, remotely.

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E.g. 1: Vertically Thrown Ball
(How would you do it?)
1.
2.
Thought Experiment
– imagine ball in air
– students predict
– students take notes
Demonstration
– teacher throws ball
– students observe
and gather
evidence
3.
4.
5.
Dry Lab (lab exercise)
– paper and pencil
– evidence provided
– constructivist lesson
Wet Lab (in the lab)
– Students gather their
own evidence in the
laboratory.
Simulation
–
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Evidence comes from
the computer
simulation.
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E.g. 1: Vertically Thrown Ball
(How would you do it?)
6.
Video analysis
–
–
8.
video provided
Computer is used to
help analyze the video;
e.g., Motion CD.
Probeware
–
–
9.
Field trip
–
7.
Video/photo lab
–
–
video/photo is provided
Students observe video
and gather evidence
from it.
–
10.
computer required
Probes/sensors gather
the evidence.
Evidence is gathered by
going to a remote site.
E.g., ride or water park
Remote access
–
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Internet access to
equipment that is
manipulated remotely
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E.g., 2 - e/m ratio of the electron
(How would you do it?)
1.
2.
3.
4.
5.
thought
experiment
demonstration
dry lab (lab
exercise)
wet lab (actual)
simulation/
animation
video analysis
7. video/photo lab
8. computer
probes/sensors
9. field trip
10. remote access
6.
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Photolab & Simulation Hybrid:
e/m lab (combinations of EBs are possible)
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Your Turn: Where can we get the
evidence on stoichiometry?
1.
2.
3.
4.
5.
thought
experiment
demonstration
dry lab (lab
exercise)
wet lab (actual)
simulation/
animation
video analysis
7. video lab
8. computer
probes/sensors
9. field trip
10. remote access
6.
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Stoichiometry Investigations: CTU

Create (inductively)
– create the stoichiometric law

Test (hypothetico-inductively)
– test the hypothesis created above

Test (hypothetico-deductively)
– test a prediction from the hypothesis

Use (deductively)
– use the well-tested stoichiometric law
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Evidential Bases for CTU Cycle
Laws Stoichiometry Equilibrium Spontaneity
—the law
—the law
—the
law

Create thought
(C)
Test
experiment
(same
evidence)
(same
evidence)
dry lab
wet lab
video lab
demonstration
simulation
computer
probes
(T)
(verify)
Use
(U)
Test
(falsify)
wet lab
(assumption of
quantitative)
photo lab
(assumption of
spontaneity)
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wet lab
(assumption of
rate rate law)
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Evidential Bases for CTU Cycle
Lab
Type
Arrhenius
Concept
Create computer
animation
(I)
BronstedLowry A-B
Lewis A-B
Concept
use falsifying
evidence
use falsifying
evidence
verify in the
laboratory
verify in a
Test
verify in the
(HI/HD)
demonstration
Use
qualitative
in computer
analysis in lab simulation
exercise
qualitative
analysis in the
laboratory
falsify in the
laboratory
falsify in a
video lab
(D)
Test
(HI/HD)
falsify in a
demonstration
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demonstration
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Evidential Bases
(Can hardly wait to see what you do with this concept.)
1.
2.
3.
4.
5.
thought
experiment
demonstration
dry lab (lab
exercise)
wet lab
simulation/
animation
video analysis
7. video lab
8. computer
probes/sensors
9. field trip
10. remote access
6.
www.CRYSTALAlberta.ca
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Evidential Bases: why?
Evidence is central to science.
 Evidence-based reasoning is one of the
foundations of all subject disciplines.
 There is now no excuse for not
gathering, analyzing and evaluating
evidence.
 More evidence has to be gathered than
time permits through wet labs.

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