While its pretty normal to associate milk with calcium, in its pure elemental form, calcium is a shiny silver grey metal! The calcium found in milk is the ionic form of calcium, having shed two electrons to form a 2 charged cation. What I think is really cool though is what you can do with just a bit of elemental calcium and some water. Calcium reacts pretty violently with water, forming a white solid called calcium hydroxide and giving off lots of flammable bubbles of hydrogen gas. If you filte