What are some symbolism objects in the book? Explain them.

Bradbury uses many symbols in his novel. A few are as follows:
Fire: Fire is a symbol that works in two ways. In Montag's society it is used as an agent of destruction and a way to get rid of problems. As Beatty says: "A problem gets too burdensome, then into the furnace with it ..." This use of fire as a way to destroy problems is negative, but Montag buys into it at the beginning of the novel, thinking it "was a special pleasure to see things eaten, to see things blackened and changed." Later, at the very end of the novel, Montag has a changed view of fire. As he stands with other men around a fire, he realizes that fire can warm people and give life. It symbolizes both death and life.
The phoenix and the salamander: The phoenix and salamander are both creatures in mythology which were thought to resist flames. The phoenix would rise again from the flames. Both are symbols the fireman use to represent the way they cannot be destroyed by fire. The phoenix, however, also comes to symbolize the new society the book readers will build at the end of the novel. Granger says:

There was a silly damn bird called a Phoenix back before Christ: every few hundred years he built a pyre and burned himself up. He must have been first cousin to Man. But every time he burnt himself up he sprang out of the ashes, he got himself born all over again. And it looks like we're doing the same thing, over and over ...

The Mechanical Hound: This metal robotic device is fashioned to look like a dog. It can paralyze or kill a person with a hypodermic needle. It is the symbol of evil in the book, of cold, cruel technology acting without humane regard for life.
Hands: Hands are often mentioned and symbolize action. Montag sometimes, especially as he first starts to take books, looks at his hands as operating separately from his will or thoughts.
Books: Books, of course, are concrete objects in the novel, but they also symbolize thoughts and ideas. The novel makes the point that it is not the books themselves, but the knowledge they contain, that matters.
To find more symbols, look for concrete objects that are named repeatedly: that usually points to a symbol.