A Project-Based Learning Unit Plan: An Inquiry into Frogs

In our standards-driven classrooms, teachers are searching for science resources to help them develop positive learning environments and meet dis-trict, state, and national standards. Guidelines are provided for creating a project-based learning unit. An inquiry into frogs is used as an example to develop a unit that can be implemented in a third-grade classroom. These guidelines provide a valuable resource for teachers in developing safe, engaging, project-based unit plans.

As state and national science standards change, elementary teachers seek out resources to help them meet standards and develop safe, positive learning environments. Project-based learning is a teaching methodology that allows teachers and students to become actively engaged in science learning and address standards. Krajcik and Czerniak [3] define project-based learning (PBL) as "an approach to teaching science that focuses on children investigating questions and problems that they find meaningful and engaging, and that spark wonderment and curiosity about the world". Hasni et al. [2] reviewed 48 articles from peer-reviewed journals written on the topic of project methods in science and technology published between 2000 and 2014. According to Hasni et al. [2], five primary features include 1) problem/question, 2) investigations/designing activities, 3) collaboration including the community, 4) technology, and 5) final projects.
PBL is not a new concept. The history of using the project method of teaching has been traced to such well-known educators as John Dewey and William Kilpatrick [10]. PBL is rooted in constructivism, a philosophy that focuses on student learning. Students make their own meaning of novel information by connecting to previous knowledge while simultaneously reflecting upon past and present experiences [11].
PBL differs from other teaching strategies in a number of ways. First, students have responsibilities that are quite different from the teacher's responsibilities.
Second, student curiosity drives the learning process as they collaborate with teachers to inquire, explore, research, and create. As students ask questions, a driving question emerges that will help drive the project. Krajcik and Czerniak [3] explain that a driving question is an important and meaningful question and one that can be safely explored and interpreted. Third, the traditional teaching model of requiring students to passively receive and recite factual information is no longer sufficient in today's technological era. PBL invites students to solve highly complex, relevant problems that require both a fundamental and 21 st century set of skills. Fourth, the central mission of PBL is to develop students into lifelong, successful learners who freely inquire about their world. As teachers use PBL, science no longer remains confined within the four walls of the classroom, but reaches beyond and allows students to take control in their pursuit of knowledge [3].
Teachers are challenged to find a balance between innovative teaching and addressing curriculum standards [12]. By using PBL, this balance is achievable.  [14].
Traditional teaching methods dictate role-specific responsibilities for both students and teachers. PBL intentionally blurs these lines, with responsibility split between the teacher and the learner(s). Through collaboration, the teacher creates a work environment where students are "free to develop their own area of interest and determine a way to learn what they want to know" [15].
Typically, teachers provide safety information, support, supervision, and encouragement for students as they develop knowledge and skills. A variety of instructional strategies are used in PBL including direct, indirect, experiential, and independent study [3]. Students learn by "doing science", which includes investigating, experiment under adult supervision, problem solving, collaborating and communicating with peers, and sharing their new knowledge [12]. As the need arises, teachers use a variety of teaching strategies and differentiated learning opportunities throughout the PBL unit. For example, if students need to use a microscope, the teacher will teach microscopy skills at that time. The scalability of this methodology allows teachers to adjust the length of the unit according to time constraints, topics of inquiry, and subject matter. PBL naturally lends itself to numerous opportunities for authentic assessment, both formative and summative, because students participate in the development of the unit and decide their final cumulative project. It is imperative that students receive feedback from their teacher throughout the PBL unit process [4].
Student curiosity is encouraged in PBL as they ask questions, explore, develop a project, and share their findings with an audience. Throughout the unit, data is collected and analyzed. Students interpret results and engage in debates/arguments based upon evidence and interpretations [16]. Scientific literacy evolves as students investigate real-life global issues and develop critical thinking, problem solving, and decision-making skills [3].

Methods
Developing a PBL Unit: A teacher wants to create a project-based science unit for students in a third-grade class. We follow and modify a ten-step process for planning a project as outlined by Krajcik and Czerniak [3]. This process includes the following: 1) Begin with Science Standards; 2) Develop a Driving Question; 3) Brainstorm Final Product; 4) Learning Strategies; 5) Constructing an Argument with Evidence; 6) Designing Projects; 7) Science Safety; 8) Assessment; 9) Integration; 10) End Product.
Begin with Science Standards: How does a third-grade teacher determine which science topics are to be taught during the school year (scope) and the sequence? PBL units begin with backward design [17] by identifying learning outcomes (performance expectations). The teacher relies upon district, state, and national science standards to identify learning outcomes. In science classrooms, children often study animals. Since frogs are found all over the world, except Antarctica, they provide an excellent model system for studying animals. If the teacher and students choose "frogs" as their animal of interest, the following NGSS will be a good place to begin: 3-LS4-3 Interdependent Relationships in Ecosystems: Environmental Impacts on Organisms; https://www.nextgenscience.org/topic-arrangement/3interdependent-relationshi ps-ecosystems-environmental-impacts-organisms.
"Students who demonstrate understanding can: Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all".
Since the NGSS are three-dimensional, Science and Engineering Practices, Disciplinary Core Ideas, and Crosscutting Concepts are identified as follows for this standard: https://www.nextgenscience.org/topic-arrangement/3interdependent-relationshi ps-ecosystems-environmental-impacts-organisms.
Brainstorm Final Product: For example, the teacher might ask the students if they are interested in studying frogs within their local community. If so, the first task is for students to select a final product that will serve as the summative assessment piece. Classmates discuss possible final products and decide they would like to write a book about frogs. Additionally, they want to present their book to students in the second-grade class. They intend to invite the school principal and the local conservation agent who occasionally presents lessons to their class.
Learning Strategies: The next step is for the teacher and students to discuss how they would like to approach this learning task. They decide they need to find out what kinds of frogs live in their community by listening for frog calls during different times of the day and evening. The class decides to contact the local zoo and find out if a citizen science program on frogs exists. A local conservation agent will be invited to talk with the class about frogs and how to identify and classify frogs. Depending upon the different types of local frogs, the class will divide into groups. Each group will study one type of frog in depth. In order to provide structure to the book, the teacher offers to guide the students in developing a template so that each group will search for the same information on each of their frog species. The template will address such questions as "Where does the frog live? What does the frog eat? How large is the frog?". As students research background information, students will become curious and ask their own questions. These questions will be written in their science notebooks and addressed in their book. Students might discover that frogs serve as the canaries in the coal mine and ask what this means. They can then do research and discover that frogs are highly susceptible to water pollution. It is important for students to cite references. What is the source of their information? Is this a reliable resource? The teacher can help students learn how to cite references. This information becomes part of constructing an argument and providing evidence that supports their statements. It is important to highlight that this is a routine activity for scientists and engineers (NGSS 3-D SEPS). Each group will become an "expert" on their frog and will present information on that frog to their audience.
Constructing an Argument with Evidence: Keeping in mind the driving question, NGSS 3.LS4-3, and overarching topic, students will "construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all". can be addressed by discussing tadpoles, frogs, and crickets in aquatic ecosystems. All frogs must return to water to reproduce. Tadpoles survive well because they are adapted to live in the water. They have gills. Adult frogs survive less well because they have lungs. Crickets do not survive at all because they are not aquatic organisms. This information will be added to the frog book. This argument illustrates the NGSS Disciplinary Core Ideas (DCIs) for Adaptation (LS4.C).
Designing Projects: The teacher ensures that student interests, learning activities, and research align with the topic and final product to spark curiosity and excitement. The teacher can introduce models, which can be made using modeling clay to explain and predict. For example, students could create a frog from modeling clay that resembles one found in their local community. Science Safety: It is the teacher's responsibility to carefully examine every activity and project for safety issues [18]. If live frogs are brought into the classroom, they can pose a safety concern. All amphibians may carry Salmonella, a bacterium that can be transmitted either by direct contact (by touching the frog) or indirect contact (by touching the water in which the frog lives). It is also important for students to wash their hands thoroughly with soap and water upon completion of all science activities [19].
Assessment: Assessment is a critical piece of PBL [3].

Conclusions
Teachers often get comfortable with one type of teaching methodology and are reluctant to change. Dole, Bloom, and Kowalske [20] found that students were able to direct their own learning within a few days of using the PBL approach. In addition, inquiry-based learning provides numerous opportunities for differentiated instruction [7] [21], which is very important in the 21 st century classroom.
Science education is for all students, not simply those who intend to become scientists [16]. It is imperative for all students to gain foundational knowledge in science in order to make well-educated decisions within their homes and communities. As students work collaboratively to create projects, they develop problem solving and time management skills [22], science and technology skills and positive attitudes as well as interest in science and technology [2]. PBL allows students to assume responsibility in the learning process as they develop both academic and social skills [4].
The teacher may initially feel uncomfortable using PBL, especially releasing control and allowing students to determine the direction of their own learning [20]. In addition, teachers especially in elementary schools often "lack relevant disciplinary and pedagogical expertise-and associated confidence-for teaching and learning in these subjects" (i.e. science and/or technology) [23]. The teacher may not have a textbook that provides content and ideas for activities. Therefore, it is the teacher's responsibility to develop clearly defined lesson plans and guide students through the PBL process. By using the guidelines described within this article, teachers will be able to create and implement their own PBL units, learn more about science and technology, and gain more confidence in their knowledge and abilities to serve as a science education leader in their own classrooms.
Why should teachers use PBL to teach science? Students perform better in science [1], are motivated to address real world science issues [ [5], and their curiosity and wonderment are encouraged [6]. Science becomes meaningful and relevant as students engage in PBL [5]. Finally, students become motivated to learn [9].