One way to conserve energy in a building is to use adequate insulation to help keep hot or cool air inside or outside of the structure. Inefficient heating and cooling of buildings is a leading residential and industrial source of wasteful energy use. In this activity, student groups conduct a scientific experiment to help an engineering team determine which type of insulation conserves the most energy—a comparison of newspaper, wool, aluminum foil and thin plastic. They learn about different kinds of insulation materials and that insulation prevents the transfer of heat, electricity or sound. Student teams collect data and make calculations, then compare and discuss their results. A student worksheet is provided.