Step 1: In a large bowl, combine the baking soda and gradually add warm water, mixing until you achieve a consistency similar to damp sand that holds its shape when squeezed. If using, add a few drops of food coloring and mix thoroughly.
Step 2: Take a small amount of the baking soda mixture and press it around a small plastic toy dinosaur, molding it into an egg shape. Ensure the dinosaur is completely covered.
Step 3: Place the molded dinosaur eggs on a baking sheet lined with parchment paper. Allow them to air dry and harden for 2-4 hours, or even overnight, in a warm, dry location. The harder they are, the longer the excavation fun will last!
Step 4: Once the eggs are completely dry, set up your excavation station. Place the hardened dinosaur eggs in a shallow tray or baking dish to contain the fizzing mess.
Step 5: Provide small cups of vinegar, along with eye droppers or small spray bottles and paintbrushes. Explain to your child that they are now paleontologists ready to unearth ancient fossils!
Step 6: Instruct your child to drip or spray vinegar onto the baking soda eggs. Watch as the eggs fizz, bubble, and slowly dissolve, revealing the hidden toy dinosaurs inside. They can use paintbrushes to gently brush away the dissolving baking soda.