Might be easier to beef some of these up for kindergarten then try to make other activities appropriate. STEM for Preschoolers 10 Science Technology Engineering Math Ideas for 3 to 4 Year Olds Left Brain Craft Brain Pin
Rain Bottle ~ fill a dry empty bottle with a box of toothpicks. Add rice (uncooked) to the bottle leaving an empty space of about 1 inches at the top. Seal the lid. As you gently turn the bottle, the rice falls through the toothpicks, sounding like rain.