24/09/2026
PHYSICS SOCIETY WELCOMES IMPERIAL COLLEGE MECHANICAL ENGINEERING STUDENT KRISTIAN SARAI
Physics Society was delighted to welcome former student Kristian (Class of 2025) for a fascinating talk exploring the physics and engineering behind something many of us use every day but rarely stop to think about: the humble bus.
Drawing on his passion for both buses and physics, Kristian demonstrated how engineering principles are embedded throughout modern vehicle design. From seat fittings and body panels to the complex systems hidden beneath the floor, he explained that virtually everything we see, and don't see, on a bus is the result of careful engineering.
Students learned about the different energy transfers taking place in the equipment powering electric buses, differentiating between hydrogen fuel cell and lithium-ion battery technology. Kristian also discussed features such as low-floor bus design, suspension systems and engine bay layouts, highlighting the practical challenges engineers must overcome to create vehicles that are safe, efficient and accessible.
Using the whiteboard and enlisting the help of several student volunteers, Kristian also introduced the concepts of centre of gravity and pulse width modulation and demonstrated how these concepts influence vehicle performance and design. These concepts gave students an insight into how the theory that they learn in the classroom is applied in the real world.
Looking to the future, Kristian encouraged students to consider whether battery-powered trains could transform rail travel in the UK, sparking discussion about the role engineers will play in developing sustainable transport solutions.
Kristian is currently in his second year studying Mechanical Engineering at Imperial College London, shared a glimpse of university life, including his timetable, laboratory work and collaborative project teams. He concluded with some valuable advice for aspiring engineers: work hard, think ahead when choosing subjects, consider undertaking an EPQ, seek relevant work experience, and look for opportunities to pursue independent projects that showcase both initiative and enthusiasm for engineering.
Thank you, Kristian, for an engaging and inspiring talk that demonstrated how physics and engineering combine to shape the world around us.