Great questions! I usually google stuff like this, but you have rethink the questions a bit...
'burn without oxygen' gets lots of results, cornell seems good:
http://curious.astro.cornell.edu/question.php?number=242That one about the astronaut is tough, I found this, but only after changing my search phrase a few times... still doesn't answer the specific question, too!
http://www.physicsforums.com/showthread.php?t=44358I know you probably aren't asking for specific answers for the individual questions, but it is possible to find the answers (or find out that no one knows yet) and for now I haven't found anything that beats google. A set of encyclopedias might keep the kid busy, but will likely result in more, not fewer questions.
(We have different sorts of questions around here; recently asked where words like 'bad' or 'good' came from and how those particular sounds came to be used, instead of others.)
