1. Document that explains the chosen concept to the animator 1

2. Electrical Resistivity in Superconductors The electrical resistivity of many metals and alloys drops suddenly to zero when the specimen is cooled to a sufficiently low temperature. This phenomenon is known as Superconductivity. Authors: Anura.B.Kenkre Course Name: Superconductivity 2

3. Learning Objectives After interacting with this Learning Object, the learner will be able to: Explain the meaning of electrical resistivity in superconductors. Predict the effect of temperature changes on the electrical resistivity of superconducting samples. 3

4. Definitions of the components/Keywords: 5 3 2 4 1 The electrical resistivity of many metals and alloys drops suddenly to zero when the specimen is cooled to a sufficiently low temperature. This phenomenon is known as Superconductivity. The temperature at which the transition to the superconducting state takes place is called the critical temperature(Tc)or the superconducting transition temperature. 4

5. Master layout or diagram Make a schematic diagram of the concept Explain to the animator about the beginning and ending of the process. Draw image big enough for explaining. In above image, identify and label different components of the process/phenomenon. (These are like characters in a film)‏ Illustrate the basic flow of action by using arrows. Use BOLD lines in the diagram, (minimum 2pts.)‏ In the slide after that, provide the definitions of ALL the labels used in the diagram 5 3 2 4 1 INSTRUCTIONS SLIDE 5

6. Master layout or diagram You may have multiple master layouts. –In this case, number the master layout. ( e.g. Master layout 1)‏ – Each Master layout should be followed by the stepwise description of the animation stages related to it. 5 3 2 4 1 INSTRUCTIONS SLIDE 6

7. Master Layout 1 5 3 2 4 1 Sample placed in cryostat for cooling Constant current supply 0.00 T=4.4K mA µ

8. Master Layout 2 5 3 2 4 1

9. Master Layout 3 5 3 2 4 1

10. Master Layout 4 5 3 2 4 1 T = 4. 4 K

11. Explain the process 1 5 3 2 4 In this step, use an example to explain the concept. It can be an analogy, a scenario, or an action which explains this concept/process/topic Try to use examples from day-to-day life to make it more clear You have to describe what steps the animator should take to make your concept come alive as a series of moving images. Keep the examples simple to understand, and also to illustrate/animate. 11

12. Analogy / Scenario / Action 1 5 3 2 4 A Mechanical Analogy of Resistance- Visualize the orange balls as electrons, flowing through a normal conductor. The nails in the board are like the atoms of the conductor, and the tilt of the board represents the voltage applied across the conductor (gravitational potential represents electrical potential). Obviously, these orange balls are going to bounce around a bit on the nails (like a pachinko machine), rather than simply falling straight through. This bouncing is analogous to electron interactions with conductor atoms which is the cause of resistance. 12

13. Stepwise description of process The goal of the document is to provide instructions to an animator who is not a expert. You have to describe what steps the animator should take to make your concept come alive as a moving visualization. Use one slide per step. This will ensure clarity of the explanation. Add a image of the step in the box, and the details in the table below the box. You can use any images for reference, but mention about it's copyright status The animator will have to re-draw / re-create the drawings Add more slides as per the requirement of the animation 1 5 3 2 4 13

14. Step 1: 1 5 3 2 4 l Audio narrationDescription of the action/ interactivity A1:”At temperature T 1 =4.4K” Show Fig1with the readings in the data boxes as indicated. The temperature meter will read T=4.4K as shown. when the learner clicks on ‘click to go to lower temperature', go to step2. Do not allow the user to click on the action button to go to higher temperature. show the 3 slides with heading A1,B1,C1 together as shown in master layout. 1.The resistance of the superconductor device is measured as a function of temperature to determine Tc. The four point probe is used to measure the resistance.. 14 Click to go to higher temperature(T) Click to go to lower temperature(T ) means For animator:do not show on screen Fig1 mA Sample placed in cryostat for cooling Constant current supply 0.50 75 T=4.4K µ mA

15. Step 1contd : 1 5 3 2 4 B1:”At temperature T 1 =4.4K” :electrons :atoms of the lattice. Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity. Always keep the size of the atoms of the lattice a lot larger than the size of the electrons. Move the electrons along the path shown by the arrows in the above figure. Do not let the electrons pass through the atoms of the lattice or through each other while moving in their respective paths indicated by arrows. The arrows show the direction of motion and the entire motion of one electron is depicted in one color. The electrons hit the atoms of the lattice and move along the path shown by the respective arrows. Show the movement of the electrons along the different colored arrows simultaneously. Fig2 15

16. Step 1contd: 1 5 3 2 4 C1:”At temperature T 1 =4.4K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show the graph as given above. Show the red spot at the place shown in the graph above. The red spot appears at the temperature of this slide, at T 1 =4.4K. Make the red dot blink to indicate that it is the current value of resistance. Fig3 16

17. Step 2: 1 5 3 2 4 Text to be displayed (if any) ‏ ‏ Description of the action/ interactivity A2:”At temperature T 2 =4.3K” Show Fig4 with the readings in the data boxes as indicated. The temperature meter will read T=4.3K as shown. when the learner clicks on ‘click to go to lower temperature', go to step3. If the user clicks on ‘click here to go to higher temperature’ then go to step1. show the 3 slides with heading A2,B2,C2 together as shown in master layout. 17 Click to go to higher temperature(T) Click to go to lower temperature(T ) means For animator: Fig4 mA Sample placed in cryostat for cooling Constant current supply 0.50 60 T=4.3K µ mA Fig4

18. Step 2 contd: 1 5 3 2 4 B2:”At temperature T 2 =4.3K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Always keep the size of the atoms of the lattice a lot larger than the size of the electrons. Move the electrons along the path shown by the arrows in the above figure. Do not let the electrons pass through the atoms of the lattice or through each other while moving in their respective paths indicated by arrows. Compared to Fig2 show less number of collisions(as the temperature is lower) Keep the speed of the electrons lesser as compared to their speed in Fig2. The arrows show the direction of motion and the entire motion of one electron is depicted in one color. The electrons hit the atoms of the lattice and move along the path shown by the respective arrows. Show the movement of the electrons along the different colored arrows simultaneously :electrons :atoms of the lattice. Fig5 18

19. Step 2 contd: 1 5 3 2 4 C2:”At temperature T 2 =4.3K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show the graph as given above. Show the red spot at the place shown in the graph above. Let it get joined to the blue spot by means of the dotted line. The red spot appears at the temperature of this slide, at T 2 =4.3K Make the red dot blink to indicate that it is the current value of resistance. Fig6 19

20. Step 3: 1 5 3 4 A3:”At temperature T 3 =4.2K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show Fig7 with the readings in the data boxes as indicated. The temperature meter will read T=4.2K as shown. when the learner clicks on ‘click to go to lower temperature', go to step4. If the user clicks on ‘click here to go to higher temperature’ then go to step2. show the 3 slides with heading A3,B3,C3 together as shown in master layout. 20 Click to go to higher temperature(T) Click to go to lower temperature(T ) means For animator: mA Sample placed in cryostat for cooling Constant current supply 0.50 50 T=4.2K µ mA Fig7

21. Step 3 contd: 1 5 3 2 4 B3:”At temperature T 3 =4.2K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Always keep the size of the atoms of the lattice a lot larger than the size of the electrons. Move the electrons along the path shown by the arrows in the above figure. Do not let the electrons pass through the atoms of the lattice or through each other while moving in their respective paths indicated by arrows. Compared to Fig5 show less number of collisions(as the temperature is lower) Keep the speed of the electrons very much less as compared to their speed in Fig5. The arrows show the direction of motion and the entire motion of one electron is depicted in one color. The electrons hit the atoms of the lattice and move along the path shown by the respective arrows. Show the movement of the electrons along the different colored arrows simultaneously. :electrons :atoms of the lattice. Fig8 21

22. Step 3 contd: 1 5 3 2 4 C3:”At temperature T 3 =4.2K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show the graph as given above. Show the red spot at the place shown in the graph above. Let it get joined to the blue spots by means of the dotted line. The red spot appears at the temperature of this slide, at T 3 =4.2K Make the red dot blink to indicate that it is the current value of resistance. Fig9 22

23. Step 4: 1 5 3 2 4 A4:”At temperature T 4 =4.15K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show Fig10 with the readings in the data boxes as indicated. The temperature meter will read T=4.15K as shown. when the learner clicks on ‘click to go to lower temperature', go to step5. If the user clicks on ‘click here to go to higher temperature’ then go to step3. show the 3 slides with heading A4,B4,C4 together as shown in master layout. 23 Click to go to higher temperature(T) Click to go to lower temperature(T ) means For animator: Fig10 mA Sample placed in cryostat for cooling Constant current supply 0.50 0.00 T=4.15K µ mA Fig10

24. Step 4 contd: 1 5 3 2 4 B4:”At temperature T 4 =4.15K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Always keep the size of the atoms of the lattice a lot larger than the size of the electrons. Show the two electrons(two dark blue balls surrounded by the light blue ring) moving together(paired in 2) along the path shown by the black arrow(do not show the black arrow on screen). The paired blue balls should not touch the atoms of the lattice while moving along the black arrow. Show many pairs like the ones shown above for a time length of about 8 seconds. :electrons :atoms of the lattice. Fig11 24

25. Step 4contd: 1 5 3 2 4 C4:”At temperature T 4 =4.15K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show the graph as given above. Show the red spot at the place shown in the graph above. Let it get joined to the blue spots by means of the dotted line. The red spot appears at the temperature of this slide, at T 4 =4.15K Make the red dot blink to indicate that it is the current value of resistance. Fig12 25

26. Step 5: 1 5 3 2 4 A5:At temperature T 5 =4.10K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show Fig13 with the readings in the data boxes as indicated. The temperature meter will read T=4.10K as shown. Do not allow the learner to click on ‘click to go to lower temperature' If the user clicks on ‘click here to go to higher temperature’ then go to step4. show the 3 slides with heading A5,B5,C5 together as shown in master layout. 26 Sample placed in cryostat for cooling Constant current supply 0.50 0.00 T=4.10K Click to go to higher temperature(T) Click to go to lower temperature(T ) means For animator: Fig13 mA µ

27. Step 5 contd: 1 5 3 2 4 B5:At temperature T 5 =4.10K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity :electrons :atoms of the lattice. Always keep the size of the atoms of the lattice a lot larger than the size of the electrons. Show the two electrons(two dark blue balls surrounded by the light blue ring) moving together(paired in 2) along the path shown by the black arrow(do not show the black arrow on screen). The paired blue balls should not touch the atoms of the lattice while moving along the black arrow. Show many pairs like the ones shown above for a time length of about 8 seconds. This image is identical to the image in Fig11. Fig14 27

28. Step 5 contd: 1 5 3 2 4 C5:At temperature T 5 =4.10K” Text to be displayed (if any) ‏ (DT) ‏ Description of the action/ interactivity Show the graph as given above. Show the red spot at the place shown in the graph above. Let it get joined to the blue spots by means of the dotted line. The red spot appears at the temperature of this slide, at T 5 =4.10K Make the red dot blink to indicate that it is the current value of resistance. Fig15 28

29. Animation design Please see the design template provided in the next slide. This is a sample template, and you are free to change as per your design requirements. Try and recreate the sections/subsections as shown in the template. 1 5 2 4 3 29

30. Want to know more… (Further Reading) ‏ Definitions Formula with derivation (if any) ‏ Graphs/Diagram (for reference) ‏ Animation Area Test your understanding (questionnaire) ‏ Lets Learn! Concepts Assumptions (if any) ‏ Lets Sum up (summary) ‏ Instructions/ Working area Radio buttons (if any)/Drop down (if any) ‏ Interactivity options Sliders(IO1) ‏ / Input Boxes(IO2) ‏ /Drop down(IO3) ‏ (if any) ‏ Play/pauseRestart Output result of interactivity (if any) ‏ What will you learn Credits 30

31. Interactivity and Boundary limits In this section, you will add the ‘Interactivity’ options to the animation. Use the template in the next slide to give the details. Insert the image of the step/s (explained earlier in the Section 3) in the box, and provide the details in the table below. The details of Interactivity could be: Types: Drop down, Slider bar, Data inputs etc. Options: Select one, Multiple selections etc Boundary Limits: Values of the parameters, which won’t show results after a particular point Results: Explain the effect of the interaction in this column Add more slides if necessary 1 2 5 3 4 31

32. 1 5 3 2 4 Instructions for the animator Instruction to the learner Results and Output Boundary limits Interactivity type (IO1/IO2..) ‏ Interactivity option 1: Step No: Same as slides 12 to 26. 32

33. INSTRUCTIONS SLIDE Self- Assessment Questionnaire for Learners Please provide a set of questions that a user can answer based on the LO. They can be of the following types: –These questions should be 5 in number and can be of objective type (like MCQ, Match the columns, Yes or No, Sequencing, Odd One Out). –The questions can also be open-ended. The user would be asked to think about the question. The author is requested to provide hints if possible, but a full answer is not necessary. –One can include questions, for which the user will need to interact with the LO (with certain parameters) in order to answer it. 33

34. INSTRUCTIONS SLIDE Please make sure that the questions can be answered by interacting with the LO. It is better to avoid questions based purely on recall. Questionnaire for users to test their understanding 34

35. Questionnaire 1. At what temperature does the sample enter the superconducting state? Answers: a)4.4K b)4.3K c)4.15K d) ‏ 4.10K 2. What happens to the resistivity of the sample as the temperature decreases? Answers: a)increases b)decreases c)remains same d) ‏ becomes zero 3. What happens to the resistivity of the sample at the transition temperature? Answers: a)increases b)decreases c)remains same d) ‏ becomes zero 4. What happens to the resistivity of the sample below the transition temperature? Answers: a)returns to normalb)decreases furtherc)it is zerod) ‏ increases a lot. 5. What happens to the number of collisions between the electron and the atoms of the lattice as the temperature decreases? Answers: a)increasesb)decreasesc)remains constant d) ‏ becomes zero. 1 5 2 4 3 35

36. 1 5 2 4 3 6. What happens to the electrons when the material enters the superconducting state? Answers: a)each electron flows through the sample without any resistance b)each electron flows through the sample with lot of resistance c)Two electrons pair up and flow together through the sample without any resistance. d)Two electrons pair up and flow through the sample with lot of resistance. Correct Answers: 1)C2)b3)d4)c5)b6)c Feedback: For Question6,If user clicks on correct answer then display ”Yes !The electrons pair up and flow through the sample together. These pair of electrons are known as Cooper Pairs. Have a look at the animation on Cooper Pairs to get a better understanding of this concept.” If user clicks incorrect answer then display “Have a look at the animation and Try again!” For the rest of the questions: If user clicks correct answer then display “Correct! Make sure you can explain the reasoning!” If user clicks incorrect answer then display “Have a look at the animation and Try again! ” 36

37. Links for further reading Reference websites: http://www.msm.cam.ac.uk/doitpoms//tlplib/index.php Books: Introduction to Solid state physics-Charles Kittel(chapter 12) Solid state physics-MA Wahab.(chapter 17) Solid state physics-Ashcroft/Mermin. (Chapter 34) 37

38. INSTRUCTIONS SLIDE Please provide points to remember to understand the concept/ key terms of the animation The summary will help the user in the quick review of the concept. Summary 38

39. Summary When you reduce the temperature sufficiently, certain metals conduct electricity without any resistance. This phenomenon is known as Superconductivity. The resistivity of the metals goes on reducing as you lower the temperature and becomes zero at the superconducting transition temperature. The temperature at which the transition to the superconducting state takes place is called the critical temperature(Tc)or the superconducting transition temperature. When the metal enters the superconducting state, the electrons in the metal pair up and flow through the sample together. These pair of electrons are known as Cooper Pairs. 39