What are 4 examples of a serene atmosphere that has significance to the play? (act.scene.lines.)
Consider this quote by Gertrude in announcing Ophelia's death:
There is a willow grows aslant a brook,
That shows his hoar leaves in the glassy stream;
There with fantastic garlands did she come
Of crowflowers, nettles, daisies, and long purples,
That liberal shepherds give a grosser name,
But our cold maids do dead men's fingers call them.
There, on the pendant boughs her coronet weeds
Clamb'ring to hang, an envious sliver broke;
When down her weedy trophies and herself
Fell in the weeping brook. Her clothes spread wide;
And, mermaid-like, awhile they bore her up. (Act IV, scene vii)
This description is both peaceful and beautiful. Death has been seen as the enemy throughout this story. Hamlet has feared it and be intimidated into inaction by it. However, Shakespeare provides this peaceful image of Ophelia in death. In life, she had lapsed into madness. In death, she is at peace. Shakespeare isn't idealizing death, but rather using these characters and descriptions to reinforce the inevitability of death and human acceptance of it.
Another serene atmosphere is in Act 3, scene iii, when Claudius is in his room alone and praying. This is significant for it forces Hamlet to see that every situation, and every person, has more than one side to their character.