Dissolve is the new vocab!

Yesterday afternoon, while I was sleeping, due to my medication, Afzal took two plastic pails, those Nata de Coco bucket. As narrated by nenek, he poured some water into one and put in talcum powder. He then used a pencil and stirred the talcum powder in the water. He asked nenek, "why did the powder dissolve in the water?". Grandma was a bit taken by that question. I don't know what grandma says but I guess I have to start digging materials to explain to him about this scientific phenomenon of "dissolve".....oh how i have forgotten my primary school science!