When memory metal is bent, it deforms. When placed into hot water, the metal "remembers" its original shape.
Butter is used to glue a piece of pasta to each disk. When the edges of the disks are immersed in hot water, the butter on the diamond melts more rapidly, releasing the piece of pasta.
A synthetic diamond wafer and an aluminum disk are held between a thumb and forefinger (to provide heat). When pressed against an ice cube, the diamond penetrates more rapidly than does the aluminum.
An annealed bobby pin is heated, then cooled quickly; this process is called hardening. The hardened bobby pin is brittle.
The tempering process, which involves heating a hardened bobby pin then cooling slowly, transforms the brittle metal into springy metal.
A metal bobby pin is heated until red hot, then allowed to cool slowly; this process is called annealing. The annealed bobby pin is very flexible.