Abstract:

The concept of electromagnetic waves is a basic one in electronic engineering and at the core of a fair number of applications including waveguides, antennas and optical fibers. However, it has been observed that, apart from requiring a fair mathematical background, students find it difficult to comprehend the nature of waves (as disturbances that propagate) as well as associated notions such as frequency and wavelength.
The paper proposes 3-hour lesson that attempts a qualitative approach to waves and electromagnetic waves that gives emphasis to the physics of waves rather than the mathematical aspect. The lesson starts with mechanical waves that are easier for students to understand and continues by applying the relevant notions to electromagnetic waves. The lecture is supported by the Kahoot gaming tool (in the technological, pedagogical and content knowledge –TPACK– framework) taking advantage of its user-friendly environment and the possibilities it offers for visualization and self-checking of obtained knowledge. The lesson takes place at the beginning of the 6th-semester course “Optical Communications” which is offered at the Dept. of Electrical & Electronic Engineering Educators of the School of Pedagogical & Technological Education (ASPETE), Athens, Greece.

The topics addressed include the following:
• Mechanical waves as oscillations that propagate from one point to the next at a finite speed v.
• The wavelength λ as the distance the wave travels within an oscillation period T; the association of oscillating points with a distance between them equal to one wavelength.
• The equation v = λf (f = 1/T being the oscillation frequency) as an immediate result of the wavelength definition.
• The derivation and physical meaning of the equation y(z,t) = A cos(2π(t/T–z/λ)) (y denoting the position of the oscillating point z at an instant t) which describes a mechanical wave propagating along the longitudinal axis z.
• The concept of the standing wave as compared to that of the travelling wave.
• Application of the notions above to travelling electromagnetic waves.
• Standing electromagnetic waves and the notion of propagating modes.

The learning benefits of the use of Kahoot mainly stem from (a) the visualization of the wave notion (which is a rather difficult concept for students to fully understand) and (b) the possibility for revision and self-checking of obtained knowledge which can performed in an active learning manner. An additional benefit is that the students can combine content’s comprehension together with the development of teaching and tool using aptitude (according to the TPACK framework) which is particularly important given that the department’s graduates can be employed as teachers in technological high schools.

Students’ response was encouraging since, despite the practical difficulties in encountering Kahoot, the majority of them (over 85%) stated that the use of Kahoot helped them enhance their understanding regarding the wave concepts. However, in the question whether the use of Kahoot should precede or follow the conventional class lecture, students’ opinions were divided, with about half of the students (particularly those with rather weak mathematical background) stating that they would prefer the use of Kahoot to take place before the class lecture.

Keywords:

Engineering Education, Electrical Engineering Education, Waves, Electromagnetic Waves, Gamification.