Instead of including rigid bodies, we opted for Special Relativity as part of the course. In our opinion, it is very stimulating for first-year students to dive into the fascinating world of Einstein and his Theory of Relativity. Moreover, Special Relativity is mathematically “light,” but it has strange, counterintuitive consequences. Through these, we can show that it is truly beneficial to work with a solid framework and to follow a rigorous approach when dealing with questions and problems. It helps students leave the high school approach—which is understandably a bit sloppy—behind and enter the world of physics.
We discuss the consequences of the fact that the speed of light in vacuum is the same for all inertial observers. We restrict ourselves to kinematics and collisions; therefore, four-forces and four-acceleration are not covered in this course. Length contraction, time dilation, and velocity transformation, however, are included. Moreover, we introduce the students to four-vectors that will help in understanding the new physics. We apply these concepts to collisions at high speeds and high energies. It goes without saying that we also do not treat General Relativity, as that requires a mastery of advanced mathematics.
It is always a joy to see when students are first confronted with Special Relativity: both confused and a bit “but this cannot be,” yet at the same time excited about this new world. The lecture breaks are then filled with students approaching us, sometimes confused, struggling to understand and appreciate the “weird” consequences, but always eager to learn. We wish for all physics students to become engaged and introduced to this new world as soon as possible.