Ice treasure hunt

I recently had a group of kids over for the evening and wanted to have something for them all to do. I used a medium size bowl and froze water in layers. each time I froze a layer I would add different things like shells, marbles, plastic bracelets, small sea life toys ect. (all from the dollar tree) it took the entire day to do layers. It took the kids at least 30 minutes to get all the treasures out. I gave the kids scoops, cups, spoons, warm water, and salt. They has fun experimenting with how to get it melt faster and everyone had there own idea it really got there little minds working.