Understanding Problem-based Learning
PBL Examples
Below is a sampling of basic problem-based lessons, tailored for specific educational levels. Each example showcases several of the important elements of PBL, such as student-directed inquiry, cooperative learning, and an interesting, relevant problem. Much like the PBL curricula developed in Project EXCITE, these examples uses environmental health as an integrating context.
ELEMENTARY CLASSROOM
The students are informed that their fictional classroom garden is failing. The plants are not growing well even though they are receiving the appropriate amounts of rain and sunlight. As caretakers of this garden, the students are charged with the responsibility of identifying and correcting the problem to ensure the health and productivity of their garden. Students may research what elements are necessary to grow healthy plants, by reading, interviewing a gardener or farmer, or even by growing some plants of their own. After much inquiry and research, the students should eventually identify soil quality as a possible cause of the problems in their garden. Students may choose to run simple “controlled investigations” by growing the same type of plant in different types of soil. Students may seek to answer questions such as, “What kind of dirt makes plants grow the best?” or “What happens if there is sand, rock, or even garbage mixed into the dirt?” As a result of their investigations, students may be able to compare and contrast different types of soil or even be able to design a new garden with optimal soil, sunlight, and precipitation conditions.
MIDDLE SCHOOL CLASSROOM
The students are asked to be consultants for an area farmer. The farmer has noticed that his crop yields have been declining every year for the last decade. As agricultural consultants, the students’ job is to diagnose the farmer’s problem and to prescribe a plan of action for the improvement of his crop yields. Students may research agricultural practices, crop yields, horticulture, annual weather reports, and water and soil quality through a variety of methods, such as interviewing agriculture specialists or farmers, reviewing historical weather reports, comparing the results of different agricultural methods, or even performing water/soil quality tests. Students may choose to conduct different “controlled investigations” designed around crop growth. Students may attempt to grow a specific crop in different soils, varying the nitrogen levels, or they may conduct field research, relating the crop yields of several area farmers to those farmers’ methodologies and/or the composition of their fields’ soil. This problem presents many research avenues for the students, and several feasible solutions to the problem. Like a true problem-based lesson, the students will be driven toward a specific “content goal,” but their individual experience and interests will dictate their specific learning pathway.
HIGH SCHOOL CLASSROOM
The students are asked to help evaluate the nutritional effectiveness of the fruits and vegetables provided in school lunches. Several studies have shown that, generally, the mineral content of fruits and vegetables has been exceptionally low in recent years, resulting in an unbalanced dietary experience for most Americans. The students must identify several causes of the decreased nutritional value observed in these types of food and propose a way to improve the quality of the fruits and vegetables provided in school lunches. To achieve these ends, students may research the “mineral cycle,” or the ways in which these nutrients move throughout an ecosystem. Students may compare and contrast the horticultural methods in which fruits or vegetables with varying mineral contents are produced, or, possibly the culinary techniques used to prepare these foods. Students will learn the significance of minerals in a human diet, the ways in which human activities deplete the ability of plants to take in minerals, and the effects of soil quality on the plant health and composition. Students may conduct controlled investigations exploring how to assess the mineral content in fruits and vegetables, or possibly, the ways in which soil quality is related to the composition of these plant products. As a result of their investigations, students will learn important concepts related to health and nutrition, horticulture, botany, geology, and, perhaps, even food preparation. They will learn important scientific concepts in a context that allows them to truly appreciate the real-world significance of these ideas.
