An annealed bobby pin is heated, then cooled quickly; this process is called hardening. The hardened bobby pin is brittle.
Credits:
- Design
- Ron Perkins Greenwich High School, Greenwich, CT 06830
- Kelly Houston Jetzer University of Wisconsin - Madison, Madison, WI 53706
- Demonstration
- Kelly Houston Jetzer University of Wisconsin - Madison, Madison, WI 53706
- Text
- Kelly Houston Jetzer University of Wisconsin - Madison, Madison, WI 53706
- Nancy S. Gettys University of Wisconsin - Madison, Madison, WI 53706
- David Phillips Wabash College, Crawfordsville, IN 47933
- Video
- Jerrold J. Jacobsen University of Wisconsin - Madison, Madison, WI 53706