Auditory processing disorder (also known as central auditory processing disorder or CAPD) is a condition that makes it hard for kids to recognize subtle differences between sounds in words. It affects their ability to process what other people are saying.
Gallium is a solid metal at room temperature, but it melts in your hands. 00:09. When gallium is in its liquid state, if feels like cold melted solder in your hands. 00:33. Melting gallium onto aluminum makes the aluminum brittle enough to break with your fingers.
The crucible material must have a much higher melting point than that of the metal being melted and it must have good strength even when white hot. It is possible to use a home made steel crucible to melt metals such as zinc and aluminum, because these metals melt at a temperature well below that of steel.