A spectacular 91AV lecture with demonstrations. Where does the energy we need to keep us alive come from? Mike Hoyland takes us through some classic chemistry experiments that show how energy is transformed (so the flashes and bangs are not entirely gratuitous!). Find out why it's correct to say that water boils at 373 degrees, what elephants toothpaste might look like, and what three thousand explosions in less than three seconds would sound like!