  We present a simple but efficient concept for the realization of blended
teaching of mathematics and its applications in theoretical mechanics that was
conceived, tested and implemented at the University of Trento, Italy, during
the COVID-19 pandemic. The concept foresees traditional blackboard lectures
with a reduced number of students present in the lecture hall, while the same
lectures are simultaneously made available to the remaining students via high
quality low-bandwidth online streaming. Based on our first assumption that
traditional blackboard lectures, including the gestures and the facial
expressions of the professor, are still a very efficient and highly appreciated
means of teaching mathematics, this paper deliberately does not want to propose
a novel pedagogical concept of how to teach mathematics, but rather presents a
technical concept how to preserve the quality of traditional blackboard
lectures even during the pandemic and how to make them available to the
students at home via online streaming with adequate audio and video quality at
low internet bandwidth. The second assumption is that the teaching of
mathematics is a dynamic creative process that requires the physical presence
of students in the lecture hall as audience so that the professor can
instantaneously fine-tune the evolution of the lecture according to his/her
perception of the level of attention and the facial expressions of the
students. The third assumption of this paper is that students need to have the
possibility to interact with each other personally. We report on the necessary
hardware, software and logistics, and on the perception of the proposed blended
lectures by students from civil and environmental engineering at the University
of Trento, compared to traditional lectures and also compared to the pure
online lectures that were needed as emergency measure at the beginning of the
pandemic.
