6 Christmas presents exploding with liquid nitrogen | 12 Explosions of Christmas with Greg Foot | HS
276To see Greg and Mike's full '12 Explosions of Christmas' bonanza here: http://www.youtube.com/watch?v=AIlji543PJw
Day six in the science behind the '12 Explosions of Christmas' sees Greg and Mike use a fantastic "ingredient". Greg likes to give the element of surprise when he wraps up his presents, but please don't copy his style...
Greg and Mike are using liquid nitrogen which is extremely cold, at atmospheric pressure it boils off (changes state from liquid to a gas) at -196 degrees celcius. Contrary to what many people think, the white stuff formed when Greg opens the dewar is actually a cloud. As the liquid nitrogen boils off and comes into contact with water molecules in the air they condense into water vapour, creating the cloud. It's not smoke!
Greg and Mike poured the liquid nitrogen into plastic bottles and capped them off. What happening then is that as the liquid nitrogen boiled off into a gas, it needed more volume which increased the pressure inside the bottles so much that the bottles themselves expanded and finally exploding under the increased pressure.
Placed inside presents filled with ping pong balls, and you get quite a surprise around the Christmas tree!
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Greg Foot is a Science Presenter on TV, Online & at Live Events, and a Wellcome Trust Engagement Fellow. For more science daredevil mayhem follow Greg here: https://twitter.com/gregfoot
Mike Sansom is a fireworks and explosive pro and runs BrightFire Pyrotechnics. For more from Mike & his explosive elves follow: https://twitter.com/ brightfirepyro
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