The product backlog is a document that contains the list of all desired work on the project. All these entries have an overall description, priority based on business value and rough estimates specified. This document is owned by the Product Owner and he/she sets the business value for each item. While the team is responsible for updating the development estimates in the document. This document is re-prioritized at the start of each and every sprint.
Sprint Backlog is a team document that is used to plan how the features will be implemented. In this document the team breaks the features into tasks. Normally these tasks are four to sixteen hours of work. If the task has an associated effort of more than 16 hrs it is broken down into a small task. The tasks are never assigned, the team member voluntarily choose the tasks as per the priority and their skills. The Sprint Backlog is owned by the team. The overall outcome of this document can be visualized as a TO DO arranged according to the business value.
The Burn Down chart is used to display the pending work in the sprint backlog. The burn down chart provides the visual representation of the overall progress of the Sprint. This is updated daily and is visible to the world.