Hidden Treasures

Kids use a hammer and chisel to unearth treasures buried in plaster of Paris. This is a great activity for a dinosaur or paleontology-themed birthday party!


Ages 5 and up; Download Printable PDF

You will need:

Cupcake pan

Plastic wrap

Plaster of Paris

Treasures to bury (coins, fake gems, beads, durable plastic figurines)

Measuring cups

Large spoon

A disposable container, such as an old coffee can

Small hammer

Screwdriver or chisel

Plastic bags to store treasures, if desired

Adult Preparation: This is messy. Do it outdoors if possible. Line the cupcake pan with plastic wrap and lay out your treasures so they are easy to grab (once you prepare the plaster of Paris, you need to work quickly!) Scoop plaster of Paris into container and add water as directed (two parts plaster of Paris to one part water for the brand I used). Stir until smooth; when you are done the plaster of Paris should have the consistency of cake batter. Drop spoonfuls of Plaster of Paris into the lined cupcake holes, and drop treasures onto the plaster of Paris. Drop more plaster of Paris over the top to bury the treasures.

Notes: (1) Kids have a lot of fun helping with the preparation, and it is good to have two people working together (one to pour the plaster of Paris, and one to add the treasures). (2) Don’t worry if the plaster of Paris begins to set before you are done. I’ve even run out, gone to the store, come back and finished, and it still works. (3) Yield will depend on how thick your treasure nuggets are, but I found that one 4 pound tub of plaster of Paris yields about 20 nuggets. (5) Plaster of Paris does seem to come off of cake pans and spoons; at least it did for me. 

Kid activity: Using the screwdriver as a chisel, hammer open the plaster of Paris to reveal the treasures. Wash off the dust and store in a plastic bag, if desired.