 To get you thinking along the right lines, have a look at these two pictures. On the left is iron powder burning in air in a shower of sparks. This is essentially what you get when you burn a sparkler. On the right is iron, also reacting with the oxygen in air, as a car in a field slowly rusts. In both cases, you get the same product, iron-3 oxide. I want you to state which reaction is occurring faster, that's pretty obvious, but then think about why it might be occurring faster, which factors from our list might be causing the difference in rate in these two cases. See you in class.