'Covered Their Heads' in the Bible

At this, Joshua tore his clothes, fell down to the ground on his face before the ark of the LORD until evening he and the leaders of Israel and they covered their heads with dust.

And David went up the ascent of the Mount of Olives, weeping as he went, with his head covered and walking barefoot [in despair]. And all the people who were with him covered their heads and went up, weeping as they went.

And their nobles have sent their little ones to the waters: they came to the pits, and found no water; they returned with their vessels empty; they were ashamed and confounded, and covered their heads.

Because the ground is chapt, for there was no rain in the earth, the plowmen were ashamed, they covered their heads.