Hello there, and welcome to yet another amazing video where you can see a YouTube user liquefying nitrogen out of the air. The video description for making liquid nitrogen reads, ‘I used a nitrogen membrane and Stirling cryocooler to liquefy nitrogen out of the air. For this video, I partnered with Starbucks to celebrate their Nitro Cold Brew.’
So, let’s talk about liquid nitrogen, shall we? Making liquid nitrogen is no easy task. In fact, it was only 150 years ago that it was made possible. Up until 150 years ago, scientists were not even sure if it was possible to make liquid nitrogen. Back in 1823, at the Royal Institution in London, Michael Faraday created liquid chlorine by accident. He subjected chlorine to high pressure.
He went on to liquefy ammonia by borrowing a mixture from Thilorier in France – a combination comprising of dry ice, snow, and ether. This mixture helped him reach a temperature of -110C. By 1845, Michael Faraday had used this mixture in conjunction with a hand pump for pressurizing gases and liquefying them except for six gases that included oxygen and nitrogen. These six gases were termed as ‘permanent’ gases.
The video description further reads, ‘A French Physicist Aimé compressed oxygen and nitrogen in tanks and then lowered them into the ocean over 1.6km deep, where the pressure got up to 200 atmospheres. Still, the gases didn’t liquefy. Only at the end of 1877 were the first droplets of liquid oxygen and liquid nitrogen produced, by Cailletet in France.’
He attempted liquefying of oxygen first by compressing it to 300 atmospheres and then cooling it to -30C. However, this was not enough to liquefy oxygen. It was only when he suddenly released the pressure that the expanding gas cooled down to (as per his estimate) -200C and he observed a mist followed by droplets that slid down the vessel’s walls.
Check out the video below where you can witness liquid nitrogen being created from scratch.