Apr 16, 2007
What connects cooling computer chips, melting car engines, and a balloon that will not pop? This week’s science video sees Robert Krampf explaining the principles behind heat sinks, car radiators, water cooling, and how to hold a balloon above a burning candle without it ever popping.
Krampf points out that, “Because we’re using fire, always be sure you keep safety in mind, and be sure you’ve got an adult around, so that you’ll have somebody to blame if something goes wrong!”
So, what is it about water that makes it absorb the heat from the candle flame so fast and so protect the rubber of the balloon from melting or burning? Water has the second highest specific heat capacity of any known chemical compound, after ammonia. This is due to the extensive but transient network of temporary hydrogen bonds that form between the oxygen atom at the centre of each water molecule and a hydrogen atom from a neighbouring water molecule. This fluxional network of loose bonds allows liquid water to rapidly absorb heat and also allows the heat to quickly be dispersed through the bulk liquid.
WARNING: Please don’t attempt this experiment with anything but water in the balloon. Water is about the only fluid that is safe to use but more to the point, it won’t work properly with any other fluid.