This blog’s focus on matters of energy and climate frequently leads to discussions of thermodynamics. One aspect of that not yet mentioned is latent heat: the energy involved in phase changes of matter. While it takes 1 calorie (not one kilocalorie, as what people call food ‘calories’ are) to heat 1 ml (1 gram, 1 cubic centimetre – don’t you love metric) one degree Celsius, it takes a lot of energy to change that 1 mL of 100˚C water into 101˚C water vapour. Indeed, it takes 540 calories to induce the phase change (turning 1 g of ice into 1 g of water takes 80 calories).
An entertaining way to see this demonstrated is to watch Julius Sumner Miller (mentioned before) talk about temperature. Another is to watch an episode of James Burke’s The Day the Universe Changed: Credit Where It’s Due. As a bonus, it explains how religious dissenters helped to kick off the coal-fired Industrial Revolution in England, eventually generating the climate change problems that confront us so dauntingly now. There is also a fair bit of talk about banking, and the role it played in industrial development.