evidently braked when falling down on a thick copper layer or inside a copper
tube, but never it can be stopped/maintained in levitation, as in the case of the
YBCO. If the magnet stops, the induced current stops due to the Joule effect. The
magnet would be stopped just falling over a conductor with resistance R ¼ 0 Ω
(an ideal perfect conductor!). Supposing that an electromagnetic induction process will be at the base of the superconductivity levitation, the resistivity of the
YBCO sample could be suddenly changed when T ~ T NL to have a levitation.
This suggest the measurement of the resistivity of a superconductor.
(S8) The experimental measurement of the breakdown of the resistivity of a YBCO
gives quantitative evidence to the phase transition for what concern the changes
from the ordinary conductor state to the superconductor state of YBCO. The
phenomenological exploration leads to the conclusion that R ¼ 0 as well as B ¼ 0
inside the superconductor. These two aspects characterize the Meissner effect.
(S9) Pinning effect in II type of superconductors is observed, when the superconductivity state is created in presence of an external field. The pinning effect, due
to the penetration of the magnetic field inside the superconductor sample as
vortexes created by supercurrents, emerges to explain the anchoring of the
magnet to the superconductor at T ~ T NL .
(S10) Students build a simple MAGLEV train, where the effect is clear because
never derail and look for different applications of superconductivity.
During each intervention module, these steps were systematically monitored,
using tutorial worksheets, audio recording of the student dialogues, and notes by
the researchers/teachers conducting the activities.
For gifted students or advanced class groups having as a prerequisite the energy
level model for the electrical conduction interpretation, we often discuss how to
interpret the superconductivity and not only to explain by means of an analogy.
Starting from the analysis of the energy of the electron system inside of a crystal
lattice, we give into account how this superconductive state can be created. Cooper
pairs, or in other words the formation of pair of correlated electrons is shown to be a
process energetically favored. The collapse of these Cooper pairs on the same
ground state is responsible of the R ¼ 0 property at the base of the superconductive
behavior.
10.5 Concluding Remarks
The recent demanding for innovation in secondary school has an important goal in
introducing modern physics topics. Our contribution for modern physics, here
discussed and exemplified for the cases of cross section and superconductivity,
may be divided into four kinds of researches: (a) Research and development for
new systems and tools; (b) Design based research to support practice with coherent
paths; (c) Empirical research to study learning trajectories, appropriation, and kind of
reasoning; (d) Teacher education and professional development. Our content
112
M. Michelini
tube, but never it can be stopped/maintained in levitation, as in the case of the
YBCO. If the magnet stops, the induced current stops due to the Joule effect. The
magnet would be stopped just falling over a conductor with resistance R ¼ 0 Ω
(an ideal perfect conductor!). Supposing that an electromagnetic induction process will be at the base of the superconductivity levitation, the resistivity of the
YBCO sample could be suddenly changed when T ~ T NL to have a levitation.
This suggest the measurement of the resistivity of a superconductor.
(S8) The experimental measurement of the breakdown of the resistivity of a YBCO
gives quantitative evidence to the phase transition for what concern the changes
from the ordinary conductor state to the superconductor state of YBCO. The
phenomenological exploration leads to the conclusion that R ¼ 0 as well as B ¼ 0
inside the superconductor. These two aspects characterize the Meissner effect.
(S9) Pinning effect in II type of superconductors is observed, when the superconductivity state is created in presence of an external field. The pinning effect, due
to the penetration of the magnetic field inside the superconductor sample as
vortexes created by supercurrents, emerges to explain the anchoring of the
magnet to the superconductor at T ~ T NL .
(S10) Students build a simple MAGLEV train, where the effect is clear because
never derail and look for different applications of superconductivity.
During each intervention module, these steps were systematically monitored,
using tutorial worksheets, audio recording of the student dialogues, and notes by
the researchers/teachers conducting the activities.
For gifted students or advanced class groups having as a prerequisite the energy
level model for the electrical conduction interpretation, we often discuss how to
interpret the superconductivity and not only to explain by means of an analogy.
Starting from the analysis of the energy of the electron system inside of a crystal
lattice, we give into account how this superconductive state can be created. Cooper
pairs, or in other words the formation of pair of correlated electrons is shown to be a
process energetically favored. The collapse of these Cooper pairs on the same
ground state is responsible of the R ¼ 0 property at the base of the superconductive
behavior.
10.5 Concluding Remarks
The recent demanding for innovation in secondary school has an important goal in
introducing modern physics topics. Our contribution for modern physics, here
discussed and exemplified for the cases of cross section and superconductivity,
may be divided into four kinds of researches: (a) Research and development for
new systems and tools; (b) Design based research to support practice with coherent
paths; (c) Empirical research to study learning trajectories, appropriation, and kind of
reasoning; (d) Teacher education and professional development. Our content
112
M. Michelini