Aluminum reacts with water so why is it used in buildings and cooking??Some help by today would be good!! :DThanxx
Aluminum reacts with water under certain conditions, but cookware does not usually present any of those conditions. Aluminum cookware takes advantage of the oxidizing process, which creates a natural protective layer over the aluminum. It doesn't react with water in the same way that chemical equations say it will because cooking surfaces are designed to maximize the oxidation effect. This is basically the same reason why aluminum foil doesn't react in water. In building materials, it's less about exposure to the elements and more about how cheap and lightweight it is. Many building materials are aluminum alloys, which makes them more susceptible to corrosion than purer aluminum, and the use of aluminium roofing material, though fairly corrosion-resistant by itself (for the same reasons as cookware), gets compromised by the proximity of other metals used in construction, like non-stainless steel nails and screws, for example, or copper pipes without insulation. The trade-off is that aluminium alloys hold their shape better and have greater tensile strength, some of which approach that of steel.
it is strong and relatively cheap compared to other metals,
There are some doctors who say not to cook with aluminum as over time the metal can enter your system and harm you. I do not know what they say about non-stick whether there are dangers or not but i don't like them anyway. I prefer iron skillets and stainless steel for pots. And the iron does get into your system but you need a certain amount of iron. I guess in buildings it is used because it is light.
The reason aluminum can be used for both building and cooking, even though is is a reactive metal (highly reactive) that reacts to water and corrodes, is because the aluminum reacts with water and dissolved oxygen (which must be present to cause oxidation) and forms a sort of oxide film which serves to protect the aluminum against further deterioration. The way this words is very complex and has to do with the purity of the water and/or it's PH level. In this way aluminum corrodes very slowly, or not at all, depending on the conditions. It is not a very good material for cooking vessels by itself because of its reactivity. For instance it will react with acidic foods and can turn them brown, etc. Plus it gets that nasty rough surface coating. But it has excellent heat retention/distribution which is why it is used in steel-clad cookware, so that the outer surface that comes into contact with the food is stainless steel which is non-reactive but the inner sandwiched layer is aluminum which gives much better cooking performance than stainless steel, which if used alone is a very bad material for pots and pans (i.e. plain aluminum would be better).
