I don't think this beautiful book should be limited to elementary students, but it could be introduced to students this young, so I will share it here.
Caren Stelson met a woman named Sachiko who had survived the Nagasaki bombing in 1945. Sachiko's family treasured a serving bowl that had once belonged to her grandmother that had somehow, miraculously like her, survived the attack. Stelson's book introduces Sachiko's touching story and carries on her meassage of peace.
Caren Stelson's website: https://www.carenstelson.com/books/bk_bowl.html
YouTube video of the book being read: https://www.carenstelson.com/books/bk_bowl.html
I think this story of loss, hope and resiliance is extremely touching. Even though the topic is quite heavy, Stelson's storytelling and Akira Kusaka's illustrations present it in a simple way that I think young children could easily relate to. I think this story would be a wonderful way to help build empathy in our students.
As a side note, Sachiko has sadly passed away. Thankfully, she opened her heart and told her story to Caren Stelson, who is determined to carry on her message. I had the good fortune to speak to Ms. Stelson during a book seminar and she showed us the bowl... once belonging to Sachiko, it has been passed to Stelson, and she treasures it and continues to tell Sachiko's story. If you read this book with your students, I believe there is a good chance Ms. Stelson would be happy to meet (virtually) with your students to talk about Sachiko, the book she wrote, and answer any of their questions.