Thanksgiving turkey and drinking water
The US CPSC says you shouldn't try to deep-fry a frozen Thanksgiving turkey. But why not?
Saw this 20-something-second long video going around on Facebook and Twitter:
https://twitter.com/USCPSC/status/801179430685147136
By itself, the video, produced by the US Consumer Product Safety Commission, tells me nothing apart from what I shouldn't be doing, no reasons or explanations. Versions of the video were also carried by The Guardian, USA Today, Reuters, NBC News, Washington Post and Scroll. (Disclosure: I work for The Wire, which competes with Scroll.) So I went looking – and found the answer on mental_floss:
The instant the frozen food hits the oil, the ice crystals melt, then momentarily sink. This exerts an upwards force on the oil. An instant later, these small sinking bubbles of water boil, expanding as they heat up and adding further force to the oil. This bubbling and forcing the oil upwards creates an aerosol of boiling oil and air violently shooting up out of the pan and towards the other parts of the kitchen.
I believe this also has a technical term, though it seems forced: 'boiling liquid expanding vapour explosion'. The explosiveness arises from a process called flash evaporation (*junior year thermodynamics memories*) – when the pressure surrounding a liquid is suddenly reduced significantly, causing some of the water to instantly turn, or 'flash', into vapour (Business Insider has the video explainer). Because gases occupy more volume than liquids, flashing can also be interpreted as an explosive expansion.
One useful application: In most desalination plants around the world, salty water is passed through a throttling valve that converts some of it into salt-free vapour, which is condensed into potable water. The remaining salty water is then sent through another throttling valve at a lower pressure to repeat the process. This is called multi-stage flash distillation. Other applications: fire extinguishers and pressure cookers being able to let off steam. Some unfortunate 'applications': boiler explosions and rapidly worsening accidents involving tankers.
