One of the ways I use this material is to paint with the rain. We sprinkle the powdered paint onto paper which is on trays and then place the trays outside for a few minutes on a rainy day. The rain water "paints" the paper.
The other is to put the powdered tempera in large shaker bottles-spices from Costco work really well. We line the table with plastic wrap, cover it with shaving cream and put out the shakers. The children shake on the colored paint and mix it into the shaving cream for a full sensory art experience.