Our latest student lecture is the first in the Quantum Theory course for second year students. Fernando Alday reflects on the breakdown of the deterministic world and describes some of the experiments that defined the new Quantum Reality. This is the sixth lecture in our series of Oxford Mathematics Student Lectures. The lectures aim to throw a light on the student experience and how we teach. All lectures are followed by tutorials where pairs of students spend an hour with their tutor to go through the lectures and accompanying work sheets. An overview of the course and the relevant materials are available here: https://courses.maths.ox.ac.uk/node/44141