Bobby Pin Lab



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Bobby Pin Lab
THEORY: Metals have numerous atomic dislocations and vacancies. When iron is heated, the atoms have enough energy to move around, creating even more crystal lattice imperfections. If this hot iron is quenched (quickly cooled), the BCC lattice structure is distorted and becomes hard and brittle.
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******* Exercise extreme caution when near the flame. ********



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PROCEDURE and QUESTIONS:

  1. Each group will receive five bobby pins.

  2. (BP #1) Take one pin and repeatedly make 45° bends on the bp curve until it breaks or your fingers are sore. Record this number.

  3. (BP #2 and #3) Heat the curve of two bobby pins to red/orange hot and let them anneal for five minutes on a cooling tray.

  4. When they are cool, document how many 45° bends the two bp withstood before breaking

  5. (BP #4 and #5) Heat the curve of the last two bobby pins to red/orange hot and quench them in the water.

  6. Document how many 45° bends the two bp withstood before breaking

  7. Explain your bending measurement results on the two different sets of material processes (annealing and quenching) with respect to the first bobby pin with no processing.


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