If you're going to be in New York City next Tuesday, there are still a few tickets left to the Kitchen Alchemy duo's class, "Chilling Out With Liquid Nitrogen."

Did PopSci's recent article on cooking with liquid nitrogen pique your interest? Learn first-hand from H. Alexander Talbot and Aki Kamozawa how to flash-freeze foods and shatter them; turn any cream into ice cream; grind olives into powder; and other kitchen-tech wonders.

The class is at Manhattan's Astor Center, August 26 at 6:30 pm. Use the secret discount code POPSCI when ordering your ticket and get 10 percent off.

Hope to see you there!

In kitchens all around the world, cooks are experimenting with liquid nitrogen. It is a dramatic and very useful culinary tool that can cool or freeze things in an instant. It is made of pure nitrogen in a liquid state. Daniel Rutherford discovered the element nitrogen in 1772. It makes up 78.1% of the earth's atmosphere by volume. In its gaseous state, nitrogen is odorless, colorless, non-flammable, non-toxic, and largely inert. Nitrogen is found in organic materials, foods, explosives, fertilizers, and poisons.

Oxygen is a good thing. Oxygen is life. But if it were much more than one fifth of our air, wed be in serious trouble. The other four fifths is nitrogen, an almost completely inert, obstructionist gas whose main effect is to get in the way of the oxygen, especially where flame is involved. For every bit of oxygen a fire consumes, it has to heat up and push away four times as much useless nitrogen. With pure oxygen, that damper is gone, and things that merely smolder in plain air go up like dry tinder. In 1967 three Apollo 1 astronauts died in a raging fire when Velcro lit up in their pure-oxygen pressurized space capsule.