Heat Treatment of a Metal Bobby Pin - Hardening
An annealed bobby pin is heated, then cooled quickly; this process is called hardening. The hardened bobby pin is brittle.
solids
Heat Treatment of a Metal Bobby Pin - Tempering - Model of the Atomic Level
An atomic-level simulation shows what happens to the metal bobby pin during the tempering process.
Heat Conduction by Diamond - Part 1 of 2 - With Ice Cube
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.
Heat Conduction by Diamond - Part 2 of 2 - With Butter
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.
Thermochromism: Mercury(II) Iodide - Temperature Increases
Mercury(II) iodide is heated to convert it from its red low-temperature alpha form to its yellow high-temperature beta form.
Hardness of Solid Substances - Grinding Selenium
Selenium can easily be ground to a powder.
Hardness of Solid Substances - Grinding Tin
Tin is a relatively soft metal that can be flattened.
Hardness of Solid Substances - Grinding Iodine
Iodine can be ground to coarse grains.
Hardness of Solid Substances - Grinding Lead
Lead is a relatively soft metal that can be flattened.
Sodium Chloride Crystal Cleavage - Demonstration
A crystal of sodium chloride breaks cleanly when broken parallel to a cleavage plane, but shatters when the knife is placed at an angle to the cleavage plane.