3b. Thermal Motion + Voltage + Grain boundaries: (Effect of defects on an electron drifting at temperatures above absolute zero) Grain boundaries, the regions where differently oriented crystals in a metal meet, are the dark lines in the figure to the They separate the light regions in between them, called grains. Grain boundaries are defects since the arrangement of atoms is more disordered there than within the well ordered grains. Rules of this activity: 1. Begin at the black electron dot. 2. Roll the die. The number rolled indicates the next atom the electron will move toward. 3. Here are the rules for moving to the next location (read carefully there are additional rules for defects!): – (1) Use the rules for the voltage activity. (2) In addition, you can only (indicated with a *). move across a grain boundary if you are on one of the adjacent atoms (3) When you are at an atom along the grain boundary, you must roll the number of the atoms just on the other side of the If you do not roll this number, the electron must scatter back to the closest number you rolled. boundary to cross it. (4) Once you have moved passed a grain boundary, you can not cross back. 4. Draw a dot in the numbered circle to indicate the new position of the electron and an arrow from the 1 2 present electron position to the new location based on the number rolled. 5. Continue this process until you have reached the end of the wire or rolled the dice 15 times. 6. Draw a fat arrow from the original to the final electron position. This vector represents the net motion of the electron. 7. Answer questions on the student sheet. Wire connected in a circuit with an applied voltage indicated by + and - signs Grain boundaries Wire *1 *3 4 2 4 6 3 1 5 1 2 4 6 5 3 1 2 4 5 *5 *6 2 1 4 2 6 3 3 5 1 2 4 3 6 4 3 2 6 3 * * 1 3 5 3 5 6 1 6 1 4 3 5 2 6 5 3 4 2 *3 4 2 1 4 3 2 5 4 2 1 6 4 *1 2 1 6 2 *5 2 3 1 * 4 6 5 3 6 3 2 1
3b. Thermal Motion + Voltage + Grain boundaries: (Effect of defects on an electron drifting at temperatures above absolute zero) Grain boundaries, the regions where differently oriented crystals in a metal meet, are the dark lines in the figure to the They separate the light regions in between them, called grains. Grain boundaries are defects since the arrangement of atoms is more disordered there than within the well ordered grains. Rules of this activity: 1. Begin at the black electron dot. 2. Roll the die. The number rolled indicates the next atom the electron will move toward. 3. Here are the rules for moving to the next location (read carefully – there are additional rules for defects!): (1) Use the rules for the voltage activity. (2) In addition, you can only move across a grain boundary if you are on one of the adjacent atoms (indicated with a *). (3) When you are at an atom along the grain boundary, you must roll the number of the atoms just on the other side of the boundary to cross it. If you do not roll this number, the electron must scatter back to the closest number you rolled. (4) Once you have moved passed a grain boundary, you can not cross back. 4. Draw a dot in the numbered circle to indicate the new position of the electron and an arrow from the 1 2 present electron position to the new location based on the number rolled. 5. Continue this process until you have reached the end of the wire or rolled the dice 15 times. 6. Draw a fat arrow from the original to the final electron position. This vector represents the net motion of the electron. 7. Answer questions on the student sheet. Wire connected in a circuit with an applied voltage indicated by + and - signs Grain boundaries Wire 1 2 4 6 5 *3 3 5 1 2 4 *6 2 4 6 3 1 5 2 1 4 2 6 3 4 *1 *5 3 1 2 4 5 3 6 4 3 2 6 6 1 4 3 5 2 4 2 1 6 4 * 1 5 *3 6 5 3 4 * 2 2 1 6 2 *1 3 3 5 3 5 6 1 4 2 1 4 3 2 2 3 1 *5 5 3 6 3 2 1 4 * 6
Nature%20of%20Resistance-CIPT_SE_rev_OCR.docx