Making Liquid Nitrogen From Scratch!

The script introduces nitrogen as a ubiquitous element, constituting 78% of the atmosphere and playing a crucial role in life. It also highlights the presence of nitrogen in the form of micro bubbles in Starbucks' Nitro Cold Brew, which is subtly sweet and frothy without added sugar. The episode is sponsored by Starbucks, who challenged the host to liquefy nitrogen from the air, a task the host is eager to undertake after trying the Nitro Cold Brew for the first time. The host then explains the process of making liquid nitrogen using a cryo-cooler, which involves compressing helium to create heat and then expanding it to absorb heat from the surroundings, achieving cryogenic temperatures necessary for liquefying gases. The host is joined by Allen Pan, a handyman and YouTuber known for his 'Sufficiently Advanced' channel and his involvement in Mythbusters, to assist in the liquefaction process. They successfully liquefy air in the room, a feat that requires condensing a significant volume of air into a much smaller volume of liquid.

This section delves into the technical process of creating liquid nitrogen. The host and Allen use a cryo-cooler to liquefy air, which they then test for the presence of liquid oxygen by observing its paramagnetic properties and its effect on a flame. They successfully demonstrate the presence of liquid oxygen, which reignites a matchstick and spreads the flame towards areas of higher oxygen concentration. The team then focuses on isolating pure nitrogen from the atmosphere using a nitrogen membrane, which selectively allows oxygen, carbon dioxide, and water vapor to diffuse out faster than nitrogen due to its selective permeability. They use an air compressor to supply compressed air and achieve high purity nitrogen by maintaining a high pressure and slow flow rate. Allen and the host make a bet on the oxygen content in the nitrogen, with Allen winning as the oxygen levels are found to be less than 5%. The team then faces challenges in scaling up the process to a dewar for better insulation, suspecting that the flow rate of nitrogen might be too high, preventing it from reaching the necessary low temperatures for liquefaction.

The final paragraph describes the team's successful attempt to create liquid nitrogen using a smaller flask and a redesigned setup that includes a tight seal and a hole for nitrogen supply. They confirm the presence of liquid nitrogen, albeit in a smaller quantity than anticipated, which leads to a humorous moment as they reflect on the effort put into the process. The host then explores the practical applications of homemade liquid nitrogen, specifically making homemade ice cream with cream, sugar, and liquid nitrogen, resulting in a smooth texture due to the rapid freezing process. The script also explains the industrial use of nitrogen in creating the unique texture of Nitro Cold Brew by infusing nitrogen bubbles into the drink, which are smaller and more stable than carbon dioxide bubbles, avoiding unwanted acidity in the coffee. The host concludes by sharing the visual phenomenon of nitrogen bubbles cascading down the sides of the glass when pouring Nitro Cold Brew and invites viewers to try it, providing a link in the description for ordering.