Create a sand that is moldable and not (very) messy by combining sand and a chemical known as dimethicone.
Affiliate links to chemicals.
*Note: The Sand can be purchased at a Hobby Store and the Astroglide can be purchased at Walmart/Target/CVS.
Mortar and pestle
NOTE: I didn't see a big difference when I "cooked" the sand. It is to remove any moisture from the sand so that the astroglide can connect better. I am in Florida and did this experiment in the summer...nothing is removing humidity for us.
The Science Behind the Reaction
Kinetic sand holds different properties with the amount of pressure being applied. When you are molding the sand, you are applying pressure and it becomes more of a solid mass. When the sand is left alone, pressure removed, it acts more like a liquid and spreads out.
Add 20 mL of dish soap, 250 mL of glue, and 4 scoops of baking soda to turn this kinetic sand into kinetic slime.
Build your sand into a tall castle. When the sand melts back into place, your time is up! Maybe use this to limit your screen time.