Which non-projected teaching aid is most suitable for illustrating concepts and ideas during a lesson?

The chalkboard is a non-projected teaching aid that is highly adaptable for illustrating concepts and ideas during a lesson. It allows the instructor to create diagrams, write notes, and engage with students in real time. The physical act of writing on the board can enhance learning, as it encourages interaction and can be adjusted based on student questions and feedback.

This medium provides immediate visibility to all students in the classroom and can be used for spontaneous demonstrations or illustrations, making it an excellent choice for fostering engagement and understanding. Its simplicity and directness allow instructors to convey information effectively while maintaining a dynamic classroom environment.

While other options, such as slide shows, interactive whiteboards, and projectors, are indeed useful in various contexts, they do not fit the definition of non-projected teaching aids. They rely on technology and can limit the instructor's ability to spontaneously alter the content based on the flow of the lesson or the needs of the students.