Expository science is the more traditional method of teaching science: students learn scientific facts, theories, and the relationships between them through direct instruction by the teacher. These programs still incorporate hands-on experimentation and “live science”; however, relative to inquiry-based programs, expository science tilts towards content mastery and knowledge acquisition. Direct instruction ensures this acquisition process is efficient. Textbooks are emphasized (starting in earlier grades than inquiry-based programs), as are knowledge tests: students are asked to demonstrate they have thoroughly learned the content of the course, and can apply that knowledge to novel and challenging problems or questions.
Inquiry-based science emphasizes teaching science as a way of thinking or practice, and therefore tries to get students “doing” science as much as possible -- and not just “learning” it. Students still learn foundational scientific ideas and content (and build on this knowledge progressively); however, relative to expository science instruction, inquiry-based programs have students spend more time developing and executing their own experiments (empirical and theoretical). Students are frequently challenged to develop critical and scientific-thinking skills by developing their own well-reasoned hypothesis and finding ways to test those hypotheses. Projects and experiments are emphasized over textbook learning. Skills are emphasized over breadth of knowledge.
Science programs that balance expository and inquiry learning equally will likely have an equal blend of tests and experiments; direct, textbook-based instruction and student-centred projects.