Over the Easter period just there, the Glasgow Science Centre did a show named ‘It’s a gas!’ which was full of scientific demonstrations using solid carbon dioxide, also known as dry ice, and liquid nitrogen. Its purpose was to show how elements were able to change from one to another of the three states of matter through evaporation (liquid to gas), condensation (gas to liquid) and sublimation (solid to gas whilst skipping the liquid phase). Part of the show involves putting inflated balloons into a dewar of liquid nitrogen and seeing what happens. Now nitrogen exists as a gas at room temperature and to be able to condense it into a liquid it has to be cooled to -196⁰C, which is a ridiculously cold temperature, and when you place a balloon of air into some liquid nitrogen it immediately starts to shrink as the air condenses into liquid to the point where you can fit a metre long balloon comfortably into a foot high dewar.
At this point we like to joke with the audience that we always get asked the question ‘what would happen if you put your hand in liquid nitrogen?’. We obviously don’t just put our hand straight into some liquid nitrogen, but we do use a replacement – a surgical glove filled with water and some red food colouring. This is put in the liquid nitrogen and left for a minute, and when removed it has frozen solid, to the point where we can snap off each individual finger of the glove. If we were to actually use our hand, and keep it in the dewar for a minute or so, then the same thing would happen to the blood in your hand, which would start to freeze and cause severe frostbite. If you were to do it for just a second though then you would be ok as the video below shows, however I would not recommend doing it personally.
The reason why I am telling you this though is that recently it was discovered that an animal based in East Asia has the ability to stay in a bath of liquid nitrogen for a whole 24 hours and still survive. And that animal is called Ozobranchus Jantseanus. Now for those who aren’t up to speed with zoology or Latin, the Ozobranchus Jantseanus is a type of leech.
What they also found is that the leeches could survive for 9 months at -90⁰C, which is roughly the coldest natural temperature measured on the Earth, with some leeches being able to stretch that out to 32 months, which is nearly 2 and a half years!
What is more amazing is that in its natural environment in East Asia, the Oobranchus Jantseanus has to only endure a minimum temperature of -1⁰C or -2⁰C, and only for a few hours at a time.
Quite how these animals have developed this resistance to extreme cold is a mystery, but ultimately fascinating.