Ineed to create a thesis and add some background information to this.
in harper lee’s book to kill a mockingbird she uses symbols to represent bigger themes and ideas within the book. four symbols that lee uses are the rabid dog (tim johnson), mockingbirds, the snow and mud that create the snowman, and the hole in the radley tree. they symbolize racism, innocence, white and black people, and boos communication with the outside world.

The Mockingbirds represent Innocence as they only do good to others and do not do any harm. Another example of mockingbirds is Arthur Radley (Boo Radley). As he does not harm anyone and protects Scout and Jem from Bob Ewell.
The Snow and mud are the white and black people. The Black people were considered even lower than the Junk (If you have noticed First came the Common Folk , then the Ewells on this side of the Junk Yard . then came the Junk Yard and then the Negroes.)
The Radley tree is the only way to communicate to Jem and Scout and it was also closed by Nathan Radley.
( I am dorry but i dont understand how Tim Johnson applies to Racism)
Please clear the last point :)

Harper Lee has used Symbolism very consciously in the book " To Kill a Mocking Bird". There are many references to the main themes. One example from the text is that even though all the evidence proved that Tom Robinson was Not Guilty but still he was declared by the Jury just because it was a Black man's word against a White Man's.