Final answer:
The intervention a nurse should implement when caring for a child in Buck's skin traction is to ensure the traction weights hang freely and are not resting on the bed.
Step-by-step explanation:
The intervention that a nurse caring for a child in Buck's skin traction should implement is to ensure the traction weights hang freely and are not resting on the bed. This is important to ensure that the traction is effective in immobilizing the limb and promoting proper healing. The weights should hang freely to provide continuous tension on the limb and facilitate realignment of the bone.