Children are natural scientists full of curiosity. This curiosity allows them to ask questions about and to investigate their surroundings. Since science is not just a collection of facts to be learned, but rather investigations that need to be made, teachers should encourage that natural curiosity in the classroom. Luckily, the "Next Generation Science Standards" ("NGSS") (NGSS Lead States 2013) allow teachers to give students the freedom to pursue their own investigations. For this reason, the project-based science (PBS) teaching method, which encourages students to make meaning out of science while conducting real-world investigations (Krajcik and Czerniak 2014), is a natural fit for 21st-century science lessons. Project-based science approaches learning the way a scientist engages in investigation of important topics. PBS teachers design their lessons around real-world problems and questions. In a PBS classroom, students design and carry out investigations, analyze and interpret data, construct models and explanations, collaborate with others, use technology, and produce artifacts to show what they have learned. This method of teaching motivates learners to explore important ideas (Krajcik and Czerniak 2014). The unit described in this article was designed for a fifth-grade classroom in a small rural school. To capture her students' curiosity, Mary Obringer planned the unit around the driving question, "What is a foot beneath your feet?" This question encompasses the NGSS standard 5-ESS2 (Earth's Systems) and disciplinary core idea ESS2.A (Earth Materials and Systems). The PBS framework meant that students would extensively use the science and engineering practices associated with that standard (NGSS Lead States 2013). She developed a four-week unit plan that would culminate in a project that asked students to create a designer soil as a summative assessment. They would then formally present their soils to a local greenhouse owner.