What do Joseph and Esther do after Florence's graveside service?

After Florence's graveside service, Joseph is handed a shovel. He heaves several shovelfuls of dirt onto Florence's casket. Finally, he hands the shovel to Esther. Esther plunges the shovel into the mound of dirt. She had always wondered how mothers buried their children, and she discovers they do so one shovelful of dirt at a time.