Sensory bottles! They used Voss water bottles. Not sure where to find them but any water bottle will work. use mineral oil for a way to slow down the materials in the bottle. I usually do 2/3 water to 1/3 oil. Can also do just rice and small objects for I-Spy bottles.
Science is all about using your senses to conclude those questions we all have! Stimulate your childs sense of smell with this cool smelling activity! Try it blind folded and really get your brain working!