logic is something that is certain. For instance if you combust something to the fullest for certain that combusted item will end up in ashes and smoke (winds similar to cloud formations) For certain...
formal is just study of logic with purely formal content and material is the branch of logic that focuses the content of reasoning.
A miteral is a object the can be used for any kind of thing>
yes they are
yes, if you can touch or feel an object, than it is a type of material