Currently, most hydrogen is made this way from natural gas. An electrical current can also be used to separate water into its components of oxygen and hydrogen. This process is known as electrolysis. Some algae and bacteria, using sunlight as their energy source, even give off hydrogen under certain conditions.
Originally, metal roofs were made of corrugated galvanized steel: a wrought ironâsteel sheet was coated with zinc and then roll-formed into corrugated sheets. Another approach is to blend zinc, aluminum, and silicon-coated steel.
The metal is produced by smelting the ore, which is cassiterite and is made up of tin (IV) oxide (SnO2). This ore is treated to remove sulphides of lead, bismuth, antimony, zinc, silver copper and iron, and then smelted in either a blast furnace or a reverberatory furnace with coke or anthracite to produce liquid tin.