Twisting a wire lab

1. Twisting a wire lab

2. Learning targets for this lab • Students will be able to describe and apply annealing • Students can relate the physical changes in a work hardened wire to the internal changes of the crystalline structure.

3. Copper has crystals • On the atomic level copper is arranged in a face centered cubic crystal structure.

4. The atomic crystal structure changes the behavior of a metal 6 planes • One way is via the number of slip planes the atomic crystal structure has. • A slip plane is a way that the atoms can easily slide over each other. • The more slip planes the more the metal can change shape without cracking. 12 slip planes 3 slip planes

5. Face centered cubic has lots of slip planes • Plastic deformation in metal takes place by sliding (slip) of close-packed planes over one another. The greater the number of slip systems, the greater the capacity for deformation. Face-centered cubic metals have a large number of slip systems (12) and are capable of moderate to extensive plastic deformation, even at temperatures approaching absolute zero.

6. This is what the crystal structure might look like in your wire Thanks Wikipedia!