You may lay it on its side or stand it on end, put Ice cream salt on the top in several places. I like the paste it is more vibrant. I put a different color on each place I put the salt and let it set and watch the colors work their way down into the cake of ice. The children are fascinated by this. After a few hours take out and discuss the form that the ice became and what happen to the liquid.
Children love to chip and melt to find the hidden treasure and the colors blend creating new colors.
You can also measure the amount of water that comes from a bucket of snow with older children. Have the children freeze milk containers or large margarine containers of water and bring them to preschool. Dress warmly and go outside. Take the ice chunks out of their containers and give each child spoonfuls of winter salt to put over the ice. Let the children use eyedroppers to dribble food coloring over the salt.