If you are a preschool teacher, you have probably experienced the wonderfulness that is "ooblick".
(Those of us in the preschool world think the mixture of cornstarch and water is so great that it deserves its own name.)
We put out bins of cornstarch and water in different ratios to create different consistencies. We also added cats and dogs as props for dramatic play.
Some children did the dramatic play thing, some did the sensory thing.
We also put toothbrushes and a bin of water for a little cleaning station. Inevitably, that water became part of the entire mix of stuff.
One beach towel laid on the table allowed me to remain at ease when minor splashes and overflows occurred.
Offering this activity (and participating in it as well) reminded me of why sensory experiences are necessary for preschoolers of all ages. Children learn through their senses and these types of experiences create the pathways in the brain that are necessary for learning. This activity itself offers learning opportunities in many domains. Children socialize and engage in pretend play. They also must negotiate space with one another. They engage in scientific exploration as they experiment with amounts and ratios and consistencies, explore the movement and momentum and of water with different levels of viscosity based on the amount of dissolved cornstarch, and experience solubility levels and capacities (you know what I mean if you've ever played with ooblick). Gross and fine motor skills are engaged depending on how the children interact with the media.
About cornstarch: Cornstarch is available in bulk at any whole sale grocer. We have several in our area. Buying those tiny boxes just doesn't make any sense to me. Be sure to discard the wet cornstarch at the end of the day, though. It gets pretty smelly after a day of being wet. Last time we left it in over the weekend, it took us several rounds of sanitizing to get the smell out of the sensory bin.