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High School Students Face Superconductivity. Lorenzo Santi Research Unit i n Physics Education Department of Chemistty , Physics and Environment University of Udine (Italy) lorenzo.santi@uniud.it. A students’ outcome example.
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High School Students FaceSuperconductivity Lorenzo Santi Research Unit in PhysicsEducation DepartmentofChemistty, Physics and Environment Universityof Udine (Italy) lorenzo.santi@uniud.it
A students’ outcome example • Summer School Pigelleto 8-10 sept 2010 (PLS-Università di Siena IDIFO3/MOSEM2) • Didactic Lab on SC - 3,5 h (MOSEM2 experiment ed poroposals). • 40 students (17 – 18 years old)
4 IBL Worksheetsfor the learningpath. Worksheet 1 – Interactionbetweenmagnets (discussionusingfieldlinesrepresentations) Worksheet 2 – Meissnereffect
The ideas of students C. Draw the field lines, after the transition. Explain the picture SC 2 – Interaction between magnetic dipoles 10/40 Tamb TNL Tamb TNL Tamb TNL Tamb TNL 4/40 4/40 4/40 22/40 the field lines do not penetrate the Ybco if T<TNL
The ideas of students C. Draw the field lines, after the transition. Explain the picture SC 2 – Interaction between magnetic dipoles Tamb TNL Tamb TNL Tamb TNL 3/40 7/40 8/40 15/40 SC produces a field (modell magnet/magnet) 3/40 the lines penetrate SC at T>TNL
The ideas of students SC 2 – Interaction between magnetic dipoles B3.1 Have the properties of the magnet canged? B3.2 Have the properties of the YBCO changed? B3.3. What are the properties changed and in which way? 12/40 «the properties of the YBCO have changed» «the decrease in the temperature produced a change in the behaviour of the YBCO» 14/40 «The disc of YBCO changes its properties. It repels the magnetic field» 5/40 «The YBCO disc is magnetized» 3/40 Re-arrangement of the atoms 6/40 NR
Summary of the results for the L path on Meissner effect • Useof the linefieldrepresentationto take into account : • The repulsion (37/40, butonethirdfollowing the magnetmagnetrepulsionscheme) • Peculiarityof YBCO (B=0) (25/40 in the rappresentation, 27/40 nin the explanations) • Changeofmagneticproperties • Featuresincluded in the explanations: • Levitation (withoutconstraints) (2/33/3) • Nullfield (2/3) • Processthathappens at the decreasingof T and itchanges the YBCO properties (40) below a threshold temperature (1/2)
Free cooling in LN Heating step by step Lab SupCond-Pigelleto
20% of answers: only the final temperature of the transition is recognized
80% of answers: The full transition interval is recognized
Conclusions • Activitieshighlymotivatingthatleadtosignificantpartecipation (and learning) • Even in frontof a complexphenomenology (seeforexample the puzzlingdifferencebetween the Meissnereffect and the pinning), the students are abletoacquire the conceptualtoolsto descrive and analyze the phenomenainvolved and todevelopemodelsthat take into account the relevantaspectof the superconductivity. • Strong integrationwith “traditional” topics in E.M.