Posted by on Oct 2, 2012 in Dinosaurs, Science Activities | 8 comments

 When I asked M what kind of party he wanted for his upcoming 3rd birthday, he enthusiastically exclaimed, ‘DINOSAURS!’ so I’ve been busy brainstorming fun activities for him and his cousins to do for his big dinosaur party.

After looking on the Internet for Dino Dig Kits I found an awesome blog called Mallard Cove Mommy, and immediately became inspired to create individual dig kits for all the kids. For my first practice attempt I made the salt dough recipe for my base, as described on the Mallard Cove Mommy site, but I wanted the dig to be more challenging than just sweeping away some loose sand, so I came up with a way to harden the sand into a nice crusty top. I mixed 2 cups of water with 1 tsp of cornstarch on the stove until it thickened, and added it to 4 cups of sand. Then I spread 2 cups of the sand mixture on top of the dinosaur skeleton and salt dough mold, and baked it in the oven at 180 for 2 hrs. When I took it out, the consistency of the sand was perfect, but as I dug to the bottom I realized what I already knew to be true; the salt dough had become wet and gooey from the sand mixture, which meant I had to come up with a new plan.

I decided to do a base of a more concentrated sand/cornstarch mixture, rather than using salt dough.
I mixed 1/2 cup of cornstarch with 4 cups of water and thickened it on the stove.

Then I added the mixture to 8 cups of sand and mixed it well (I was making 8 kits, and each kit needs 2 cups of the sand mixture for its base, so I made a double batch). Once the ingredients were all incorporated, I pressed 2 cups of the sand mixture into the bottom of a small aluminium pan I had purchased from the dollar store, and pressed the dinosaur fossils into it (I made sure to rock my skeletons back and forth a bit in order to get a good impression so they would fit back into the mold later).

When I was satisfied with the imprints, I took the skeletons out of the pans and baked the sand molds for 2 hrs at 180.

When I took them out of the oven they were as hard as concrete, which is exactly what I wanted! I fitted the Dino skeletons back into their molds and sprinkled some loose sand on top of the fossils.

Then I made a more diluted version of the sand mixture for the top that the kids would actually be able to dig through. This time I only added 2 tsp of cornstarch to 4 cups of water, and stirred it while it thickened on the stove. Then I added the cornstarch mixture to another 8 cups of sand (again, I ended up making a double batch for my 8 kits). I shovelled 2 cups of the diluted sand mixture on top of each the dinosaur fossils, and smoothed it out. I baked the kits for another 2 hours at 180.

When they came out of the oven, I was really pleased with the consistency of the sand. It wasn’t too hard for the kids to break through on their own with the tools provided, and yet it would give them a bit of a challenge. The only thing I was disappointed with was that the base had absorbed the water from the top layer, and was no longer super hard, which meant that the fossil imprint would be lost as soon as the dinosaurs were excavated. Maybe if I had baked them longer the base would have hardened  up again, but seeing that the sand was already at a good, crusty consistency, I decided to leave it as is.

I printed off the corresponding Dinosaur cards from the Dinosaur Train website, as suggested on the Mallard Cove Mommy blog, and glued them onto the insides of the lids.

Lastly, I sealed the containers, printed off some labels, and gathered some excavating tools for each of the kids to use (a plastic spoon and knife, a long wooden coffee stir stick, a magnifying glass, and a paint brush), which I purchased from the dollar store.

I’ll let you know how the excavation went in my next blog post about M’s Prehistoric Dino Party!