Pre-bake the sand to remove any and all water (1-inch deep layer in a pan at 250 for 30 minutes; let cool completely before handling).
Add one cup white play sand and 6 tablespoons cornstarch to a large mixing bowl; mix until well combined.
Add one tablespoon of thermochromic pigment; mix well until combined.
Mix 1 cup water with 1 teaspoon of dish soap.
Mix well to combine.
To the bowl, slowly add while mixing 4 tbsp water.
Add more water, slowly, as needed until the sand is the desired consistency.
Mold into shapes and cut as desired.
The heat of your hands will change the color of the sand as you play with it.