Molecules in Motion - 1979 Christmas Lectures 2/6

Explore the fascinating world of molecular motion through this 53-minute Christmas Lecture delivered by Eric M. Rogers at The Royal Institution in 1979. Discover how air exerts pressure and what this reveals about air molecules through compelling experiments that demonstrate molecular bombardment of tiny visible particles. Learn to measure the spacing of molecules in air and estimate their incredible speeds through hands-on demonstrations. Witness the properties of liquid air and examine the evidence it provides about molecular behavior. Understand the principles behind jet propulsion by observing how hot exhaust gases blast backwards as their molecules rebound from internal walls, pushing the engine forward. This second lecture in Rogers' six-part series combines theoretical concepts with spectacular experimental demonstrations, making the invisible world of atoms and molecules tangible through what Rogers calls a "circus of experiments." The presentation addresses fundamental questions about atomic structure and molecular behavior using indirect experimental methods and imaginative models, providing viewers with first-hand acquaintance and confidence in understanding these microscopic phenomena that are far too small to be seen directly.