In this time of concern over climate change due to the atmospheric greenhouse effect, teachers often choose to extend relevant classroom work by the use of physical models to test statements. Here we describe an activity in which inexpensive backyard models made from cardboard boxes covered with various household transparent materials allow students to explore how transmission of visible and infrared light can affect the temperature. Our basic setup is shown schematically in Fig. 1, in which a black-lined box with a thermometer in contact with the bottom is covered with transparent (to visible light) household materials.