The students designed and built an insulator for a hot water-filled soda can using various materials like cork board, emergency blanket, duct tape, rubber foam, felt, aluminum, and steel wool. They explained how each material's properties help or hinder insulation. Their insulator had multiple low-density, air pocket-containing layers and reflective aluminum. It worked relatively well but could be improved with a foam core and less duct tape. Future designs should use denser core materials and minimize heat-conducting components like aluminum.