Feynman would relate these in more detail in Surely You're Joking, Mr. Chapters 35 and 36 of Volume 1 take on topics related to vision, such as the anatomy of rod cells, how the molecule retinal in photoreceptor cells works, the resolution of the compound eye of the bee and the mysteries of colour vision - reflecting his 1960s adventures in biology. How many physics books have a section entitled “More organic chemistry”? In it, he shows us how to use simple quantum-mechanical models to work out the spectrum of energy levels of different types of molecules.

From lightning to the periodic table and the energy levels of chlorophyll, he is not interested in naming conventions that separate different academic disciplines. One of the most delightful features of the Lectures is that Feynman is constantly on the lookout for physics writ large. And he similarly provides an advanced but accessible introduction to elasticity - the likes of which, unfortunately, advanced physics students rarely see even now. When talking about Brownian motion (the random movement of particles in a gas or liquid as they collide with molecules of that medium), he elegantly teaches us the fluctuation–dissipation theorem, which relates how rapidly particles diffuse to the drag force they experience, without ever naming it as such. These same ideas return in his treatment of the elliptical motions of planets.

This is seen nowhere more impressively than in the way he develops optics by thinking about the transit of light rays as they pass through various media, whether lenses or the atmosphere. Feynman also repeatedly appeals to 'variational' principles based on minimizing quantities such as travel time (pictured). For example, his fascination with the way that Newton's second law of motion, F = ma, can describe the motions of large, composite objects such as galaxies leads intuitively to the profound idea of the centre of mass. He works this magic even in areas often thought to be the most boring parts of the curriculum.

Richard feynman lectures on physics pdf