Transcript New » topics

Attracting students towards
physics
A matter of topic?
Laurence Viennot
LSDP, University Denis Diderot (Paris7)
Research on students’ motivation
• A large part of this research domain is mainly focused on
topics likely to raise interest in young people
ex: ROSE Schreiner & Sjøberg, 2005
• A few studies also explore other aspects (type of
activity, context) likely to attract students’ interest
ex Häussler et al.,1998; Stark & Gray, 1999; Lavonen et
al., 2005; Trumper, 2006
Searching for exciting topics
• In recent school curricula or university syllabuses : a search
for topics that are
- relevant (physics in context),
- exciting (« new », beautiful , makes you dream,
incredible…)
- preferably: both
• Popularisation papers or events (ex: year 2005):
- same concern
But…
Attracting
students towards
physics: an
irrecductible
alternative?
Formalism:
a stress to keep hidden?
The nature of science:
distorted?
What about
the pleasure of reasoning?
What about the value of the
internal consistency,
conciseness , and predictive
power of physical theories?
-What do we do with (reputedly) attractive topics?
-How to make old topics (usefully) attractive?
From the standpoint of:
the value of the internal consistency,
conciseness and predictive power of
physical theories
Appeal of « new » topics
An example:
Durban (ICPE 2004)
« What physics should we teach ? »
• Quantum gravity for undergraduates? R. de Mello Koch
• A unit on (...) determinism and chaos for
introductory physics students
P. Laws
• Illustrating quantum entanglement in an elementary
context
G. Roston et al.
• Quantum mechanics for everyone: can it be done
with technology?
D. Zollman
« New » topics:
with technology
• Quantum mechanics for everyone: can it
be done with technology?
D. Zollman
…for high school students and for non-science college students
Getting round a discouraging formalism
http://web.phys.ksu.edu/vqm/
… discrete states in quantum wells. The (…) program
enables students to match wave fonctions visually at
boundaries. They find that if they pick a random energy
for a particle in a square well, the wave function does not
fit* at both boundaries.
*i.e.: they cannot obtain « smoothness »
They get the functions
matched up on one side, then
try to meet the conditions on
the other side. They can’t do it.
Only for certain energies can
they meet the boundary
conditions on both sides.
A priori: undeniable positive outcomes,
To give a first idea of…, students in an
active attitude, excited…
What did they learn?
Only for certain energies can they meet the boundary
conditions for both sides…
Our testing indicates that they are learning the material
Some non-obvious questions
What does it mean to « learn the material »?
Concepts and links between concepts?
Given this simulation, what is their view of the
generalisability of what they see?
What is the kind of reasoning that students are
expected to use, on the basis of their
« learning »? (in the absence of a computer)
A « new » topics: with (transparent) technology
• A unit on (...) determinism and chaos for
introductory physics students
P. Laws
Priscilla Laws
Iterative spreadsheet modeling
 net =  grav +  damping +  springs +  driver .
I= mR2 + 1/2( MR2 )
A priori: undeniable positive outcomes,
To give a first idea of…, students in an
active attitude, …
What did they learn?
Finding a map for this jungle?
From the standpoint of:
the value of the internal consistency,
conciseness and predictive power of physical
theories
Several interrelated concepts
... to understand, (…) …,
that determinism is there…
… although « the system motion becomes chaotic when
driven at certain frequencies. »
Why?
« Students are asked to observe the natural
oscillation frequencies of the apparatus when it is
configured in different ways. This helps them
understand why the system motion becomes chaotic
when driven at certain frequencies. »
What did they learn?
Instructors expected them to be surprised that the state of a
chaotic system is unpredictable when the torques acting on
it are known.
Instead, students often commented that Laplacian
determinism is not feasible because of quantum
effects.
…, we found that the Chaos Unit is both vexing and
exciting to our students.
Non-obvious questions…
Beyond « showing » students that
their predictions fail to describe what happens,
how do we
take into account students’ common ideas ?
Non-obvious questions…
Beyond working with a particular device, and
« seeing » …, do students grasp some
• concepts, links between concepts,
• understanding of the generalisibility, idea of a
domain of validity
• feeling of having an explanation (beyond a
phenomenology)
• tools available to reason about a new situation
?
…not to be overlooked,
whatever the approach:
simulation, analytical, analogical…
A « new » topic with simple tools to reason
Imaging Ogborn and coll. 00, Advancing physics (AS-UK)
A set of interrelated concepts
Pixels, resolution, logarithmic
scale, information in imaging,
image processing
Replace each pixel
by the mean of its
value and those of
its neighbours
…median…
« New » , « in context » ,.
and
enabling students to reason.
« New » topics: mission impossible?
Certainly not, but a need for thorough reflexion,
careful selection of goals and strategies…
The question is not so much to get round the
formalism as to
- provide students with some tools for reasoning
in order to
- help them go further than being «both vexed
and excited ».
A need to evaluate the innovative sequences
Komorek & Duit IJSE 04
From the standpoint of:
the value of the internal consistency,
conciseness and predictive power of
physical theories
Ordinary topics and the value of
internal consistency
Physics as an internally consistent and
unifying description: an attractive idea?
If yes, then it is worth considering
the risks of inconsistency
some possible ways of showing the
limited but great power of physics
An example with a very ordinary topic …
A hot air balloon
pO
pO
pO
A typical exercise:
•
A hot air balloon …a total mass
of…
•
Whatever the temperature of
the air in the balloon, its
pressure will be the same as
the surrounding air. (……….)
•
…Show that to achieve the lift
off…must be heated to about
….° C.
pO
Archimedes upthrust : a matter of weights
Fbasket+… + gMair-inside = gM air-outside-sameV
Tout
Tin
pin = pout = p 0
Mair-inside = rair-inside V
Mair-outsider=
F
sameV
= rair-outside V
Mmol p /RT
0
But…
pO
pO
Serious consequences
pO
g
pO
« Local » ignores « global »
and vice versa...
Archimedes, where are you?
Global and local reconciled
pin > pout
Global
rin< rout
Archimedes
OK
Dh
pin = pout
Dpin= -ringDh
Dpout= -routgDh
p
pin> pout
Aperture
P
Top
Local
OK
Viennot 04
Dh
p
pO
Students’ reactions
pO
O
p
O
• No spontaneous detection
(1st year: 15 interviews* + degree: N=32*+16**)
(same for 76 Teachers*)
• Guided analysis (1 year: 15 interviews*, degree:
-accessible ,
-takes time but worth it
-raised pleasure
st
Viennot 04*, 06*
Mathé Viennot 07**
21*+15**)
Thank you, you have
made me think
A student: using critical sense: needs to be taught
Thinking further?
The weight of a gas… only one molecule
A particule
moving vertically in a motionless box,
elastic collisions on the walls
z+Dz
z
The mean force (in time) exerted by
this particule on the box equals the
weight of the particule
True or false ?
An elastic collision …
A molecule (m) hits a wall
perpendicularly with a velocity v et
leaves this wall with velocity -v.
v
Change in linear momentum of the
particule:
Dp= -2mv
Change in linear momentum of the particule at
the top of the box
Dptop= -2m (v + D v) u
v = (v+ D v) u
D v<0
u
v (-u)
Change in linear momentum of the particule at
the bottom of the box
Dpbottom= 2mv u
Change …during a « cycle » due to the box (up and
down, two collisions)
Dpparticule,cycle = -2mDv u
Change …during a « cycle » (up and down)
v = (v+ D v) u
due to (two collisions with) the box
u
Dpparticule, cycle= -2mDv u
Free fall
Dv = -g Dt u
v (-u)
Mean force exerted on the particule by the box
during a cycle (2 Dt where Dt is the duration of free fall)
fmean force box-on-particule =
Dp/2Dt
f mean force box-on-particule = mg u
Third law
v = (v+ D v) u
f mean force box-on-particule = mg u
v (-u)
Therefore
f mean force particule-on-box = -mg u
The mean force exerted by the particule on
the box is equal to its weight
It had to be so
The mean position (in time) of the centre of mass of
the particule during a cycle is the same for all the
cycles
A Newtonian balance of forces :
f mean force box-on-particule + ( -mg) u = 0
f mean force box-on-particule = mg u
U
An inhomogeneous slice
z+Dz
Links between
statics et dynamics
individual et collective
« it has to be so… » and «because»
z
z
z+Dz
z
A few reactions
Destabilised trainee teachers
(first professional year, N=19)
Y N ?
Is it true that …
The mean force exerted by the particle on the box is equal to
its weight?
5 10 4
z
z+d
z
z
The molecules, via collisions, exert the same force on the
ground as if all the molecules of the column above were pile
up, motionless, on the ground .
5 9 5
A slice of atmosphere … , the force df exerted on it by the
air around ... and its weight dP are such that dP + df =0 ,
with dP=-gr(z)dzdS u
8 3 8
The weight of a column of atmosphere equals the
force exerted on the ground by this column 11
5
3
Students’ reactions
z+Dz
(3rd year univ., N= 13; trainee univ. teacher, N=9)
z
• Guided analysis (in group, 20mn)
-accessible ,
-worth the time it takes
-raised pleasure
- never thought before
Students’ reactions , more details
(3rd year univ., N= 13)
First question about a column of atmosphere:
Yes
13/13
Then, question about a unique molecule:
Yes
1/13
Then, the preceding analysis is presented:
Students’
comments
-
Explains simply a fundamental question that is not very
easy to explain simply to students intuitively. (4,4)
-
I like thinking about things that I never thought about
before. (4,4)
Finally (without interval):
N=13, 3rd year univ.
Yes,
ranked 3 ou4
on a scale
1
4
No
Yes
Pleasure?
1
12
9
Worth the time it
takes?
0
13
9
An experienced teacher, interview
(Only one, « agitated », molecule in the box)
-P1 It comes down to saying being at the botttom of
the box and therefore… transmitting the weight,
uhm, by the bottom of the box or moving all around
the box and exerting actions, pressing forces,… it
comes to the same thing. Why does it come down
to the same thing… uhm…????
(After explanation)
-P1 Oh yes, it’s because usually, when we study a
gas, we neglect weight… we do not do it in a
gravitational field …
…We have shown in that box there why the pressure
was greater than there, we have shown it with g.
From the hot air balloon to the single molecule
From macro-global and macro-local
to nanoscopic
z+Dz
z
From the gas
in a horizontal test tube
to an atmosphere
A continuity of mutually consistent viewpoints,
in the frame of Newtonian mechanics
Ordinary topics, but less common questions…
In general terms,
students’ declare their appreciation …
Limited inquiry
Reasons for satisfaction: students’ ranking (1: very high)
Ranking 
1 or 2
1,2,3
7 to 10
Concrete, visible, sensitive content
16
21
1
2.69
Students are active
8
15
1
3.15
I have understood everything, it was 11
simple
16
3
3.52
Link with everyday life/ recent
developments
6
14
1
3.46
Surprise
11
16
4
3.92
Beautiful reasoning, coherence, links 14
19
1
3.21
Spectacular phenomena, dream
7
9
6
4.54
No mathematical formalism
2
2
8
5,08
Debate, developing critical sense
7
15
3
3.52
Item 
29 3rd year univ-students
Mean
rank
…a stress on coherence, and on links.
Two lines of action
-Many situations, a unique formalism
-A unique situation, different approaches
Many situations, a unique formalism …
• The harmonic oscillator (60s)
• √N, Poisson, exp-t/: radioactive decay etc
See Advancing Physics IoP (UK, 2000- Ogborn, in
particular: Imaging++) , Grade 12 in France (2000)
• Boltzmann factor, Change and Chance (Black,Ogborn,
70s),… Advancing Physics A2 (2001)
• And also d=vt
(Viennot/Leroy: delayed signals GIREP sem.2004)
X
t
but also
…different viewpoints for a given situation
p
pO
pO
O p
O
See also macro-meso:
Besson Viennot 04
z
z+Dz
z+dz
z
z
Final comments
without a strong exigence of consistency,
dislocated physics a near certainty
p
pO
pO
O p
O
Strong
concern for
consistency
and links
Intellectual
satisfaction
A linkage worth exploring further
• « It’s worth it…
…provided we are
taught how to do it »
If teachers agree to try ….
« Good for us,
not for them »
Inciting teachers to try…
what can we do?
« Good for us,
not for them »
Rational factors
(2 =20,38, p=0,001).
Teacher optimism:
to be increased
Emotional factors
…creating the
conditions for them
to hear:
Thank you, you have
made me think
The conditions for teachers to hear…
……
Thank you, you
have made me
think
commonly thought of as limited to non-classical activities
(projects, SPU,…) with « relevant » , « exciting », …topics ?
Suggestion: consider it
possible and necessary to
raise intellectual
satisfaction with
ordinary topics
p
pO
pO
O p
X
z+Dz
O
z
t
….
Some references
• VIENNOT L. 2004, ICPE meeting, Delhi
• VIENNOT L. 2006.Teaching rituals and students'
intellectual satisfaction, Phys. Educ. 41 pp. 400-408.
http://stacks.iop.org/0031-9120/41/400.
• MATHE, S. and VIENNOT, L. 2007, The concern for
coherence among future science mediators, ESERA
X
meeting Malmö.
•
•
VIENNOT L. & LEROY J.L. 2004. Doppler and Römer: what do
they have in common? Phys. Educ., vol. 39, issue 3, pages 273 280.
BESSON, U. & VIENNOT L. 2004. Using models at mesoscopic
scale in teaching physics: two experimental interventions on solid
friction and fluid statics, IJSE, 26 (9), pp1083-1110.
[email protected]
p
pO
pO
O p
O
t
• Häussler, P., Hoffman, L., Langeheine, R., Rost, J. & Sievers, K.
1998. A typology of students’ interest in physics and the distribution
of gender and age within each type. International Journal of Science
Education, 20(2), 223-238.
• Lavonen, J.; Juuti, K.; Uitto, A.; Meisalo, V. & Byman, R. 2005.
Attractiveness of Science Education in the Finnish Comprehensive
School (pdf). In A. Manninen, K.Miettinen & K. Kiviniemi (Eds.),
Research Findings on Young People’s Perceptions of Technology
and Science Education. Mirror results and good practice. Helsinki:
Technology Industries of Finland.
• Schreiner, C. & Sjøberg, S. 2005. Empowered for action? How do
young people relate to environmental challenges? In S. Alsop (Ed.),
Beyond Cartesian Dualism. Encountering affect in the teaching and
learning of science. Dordrecht: Springer.
• Stark, R. & Gray, D. 1999. Gender preferences in learning science.
International Journal of Science Education, 21(6), 633-643.
x
T
S
t
Key words
Consistency
Unifying power
Durban 2003, ICPE
Functional thinking
« New » topics: with analogy
• Komorek & Duit (04 and before)… entry: a phenomenology
Known laws
Limited predictibility
Why?
« Often in an instable
situation »
« Sensitive, labile states
of equilibrium »
Why? « … due to a large number of variables »
Professeurs en formation, quatre questions de suite
(PLC2, N=19)
O N ?
Réponses
identiques
Aux quatre
questions
à trois questions
seult
à deux questions
seult
1 7 1
z
z+dz
0 20
2 2
z
0 10
1 1 0
5 11
A « new » topic with simple tools to reason
Imaging Ogborn and coll.. 00, Advancing physics (AS-UK)
A set of interrelated concepts
Pixels, resolution, logarithmic
scale, information in imaging,
image processing
Very large implications, domain of validity
« New » , « in context » ,.
and
enabling students to reason.
Return to the
atmosphere
• This reasoning is valid no matter what the value
of v.
• It applies equally well to the vertical component
of any non-vertical particular velocity.
• The collisions between particles keep the same
quantity of motion. The fact that they can
intervene during the period considered does not
change the mean force exerted over time by the
molecules on the sides or the bottom of the box.