I burned my hand on the oven rack. is it a good idea to put ice over it?

Yes: Sure ice does wonderful things for the first 48 hours after a burn. First, it has numbing qualities by overloading nerve endings with cold feeling which decreases the pain fibers from saying "ouch" in your head. Second, the cold does decrease and prevent inflammation. After 2 days though, ice wont help with swelling. If you have no sensation at all over the burn, it may be a deep burn, see an md.