Shulman (1986) described how qualification and eligibility tests historically revolved around basic content like reading, writing, arithmetic skills, needing teachers to demonstrate subject matter knowledge before teaching. However mere knowledge does not guarantee effective instruction, requiring interplay between content and pedagogy. The pendulum swings back and forth regarding how new knowledge is acquired, with implications for classroom management, organizing activities, planning lessons and judging understanding among others. Content is represented in different ways to accommodate students, with teachers asking questions at various Bloom taxonomy levels, probing alternative views to accumulating wisdom of practice. Shulman (1987) highlights an issue that teaching is conducted without a history of practice or audience of peers. Though learning ultimately remains student responsibility, educators design teaching for comprehension, reasoning, transformation and reflection so unknowing comes to articulate what they know. Transformation involves preparation, selection, adaptation within instruction and evaluation, bridging comprehension and thinking for students through lecture and demonstration towards cooperative learning and reciprocal teaching. Learners work through misconceptions and expectations, reasoning through discussion cycling seamlessly between phases.
An example of PCK that comes to mind is teaching basic motion concepts, going beyond reading definitions of displacement, velocity and acceleration in textbooks, to comparing and contrasting scalars and vectors, making everyday connections to speedometers and marketing to help audiences build upon previous knowledge. The significance in distinguishing quantities that have magnitude with and without direction, needs to convince learners why they cannot maintain pre-existing beliefs when confronted with contradictions. Science naturally has self-corrective features in building increasingly complex models to explain observations and make predictions. Labs can be teacher-directed or student-centred to investigate terminal velocity and ramp height for example. Technology comes in when motion sensors are utilized to construct position-time and velocity-time graphs in real time, learning how to interpret and change between graphs. Simulations like PhET Moving Man can be used to introduce, teach or reinforce concept knowledge.
References
Shulman, L.S. (1986). Those who understand: Knowledge growth in teaching. Educational Researcher, 15(2), 4 -14.
Shulman, L.S. (1987). Knowledge and teaching. The foundations of a new reform. Harvard Educational Review, 57(1)1-23.