[KNO3]

First post on this forum, hope it goes well:
So I've started getting into chemical reactions, mainly trying to make rocket candy(KNO3 + Sucrose/Glucose/Fructose...etc...etc) but I kinda started to look at Thermite and Gunpowder(not to make it though) and I've got a couple questions:
Why is sulfur used in gunpowder to lower ignition temp.
Why are only metal oxides used in thermite
What is the purpose of using metal oxides instead of just any old oxidizer
Are there any kinds of common household oxidizers

[Borek]

Why don't you start with the forum rules, which clearly state we don't discuss pyrotechnics?