From a young age, children encounter different materials and learn color, hardness, texture, and shape. Focusing on observable properties is an engaging way to introduce young children to matter. In this investigation, students use observations and engineering design to decide which material would make the best roof for a doghouse. The authors used the 5E model (BSCS and IBM 1989) to create an engaging inquiry-based activity to meet standards and make real-life connections to physical science content. Their second-grade students enjoyed the activity and came to understand how physical properties can determine how a material is used.