While curriculum designed as project-based learning is not suitable for use with every science standard, this methodology can be used when teaching concepts that naturally contain some flexibility. With small adaptations, teachers can implement these practices into the classroom regardless of the grade level. This article provides a detailed account of the instruction and learning that took place in a first-grade classroom. A five-day project-based learning experience was implemented that included an introduction to new children's literature, hands-on investigation, completion of an activity book, and guided research which culminated with a challenge for the students to construct a toothbrush from the materials found in an animal's natural habitat.