For Martin Luther King Day last year my pre-k decorated an old sheet by spraying different colors (food coloring and water) from a spray-bottle all over it. We watched the colors mix and talked about how people are different, just like the colors, but how they can live/work/share together (just like MLK believed). Then after the sheet dried I cut it into squares and let everyone take a piece home.
Martin Luther King Jr Day Art
Martin Luther King Jr Day Art activities for preschoolers through second grade.