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Freezing heads in liquid nitrogen: The science behind 'Jason X'
Did Jason's trip to space also go past the realm of science?
Much like its central character, the Friday the 13th franchise just can’t seem to die. Since the original installment blazed onto movie screens in 1980, we’ve been treated to twelve feature films, a television series, books, comics, and a surprisingly fun video game.
Over the course of Jason Voorhees’s storied afterlife, he’s been stopped — albeit temporarily — in a number of creative ways and he’s even been to Hell. Yet, in the franchise’s tenth installment, Jason X, Voorhees ended up somewhere he had no business being, aboard a spaceship in outer space.
While Jason X might represent the moment when the story officially jumped the shark, it did offer an opportunity for what is perhaps the coolest and most brutal kill in Voorhees’s entire career. After awakening from cryogenic sleep, Jason grabs Adrienne Thomas, a scientist aboard the ship, and plunges her face into a conveniently located vat of liquid nitrogen. After a few seconds, she emerges from the subzero liquid frozen solid. Not satisfied with the efficiency of the murder, Jason smashes her face into a countertop, where it shatters into a few dozen pieces. Despite being bloodless, it’s gruesome in a way so many of Jason’s other kills aren’t.
That scene got us wondering, provided you had access to a spaceship, a vat of liquid nitrogen, and a seemingly immortal serial killer, would that kill play out the way it did on screen?
HOW DOES LIQUID NITROGEN WORK?
Do you remember the states of matter you learned about in grade school? Matter tends to exist in one of three states either gas, liquid, or solid. Which state it is in relies largely on its temperature and pressure. Nitrogen, in and of itself, is not dangerous. If it were, we’d be in a heap of trouble.
When we talk about breathing, we’re usually talking about oxygen. That’s because oxygen is the part of the atmosphere that reacts with our biology and helps to power all of our various tissues to keep our meat suit trucking along. In truth, mostly what you’re breathing is nitrogen. Earth’s atmosphere is comprised of about 78 percent nitrogen, with oxygen making up only 21 percent. The remaining 1 percent is mostly argon and a negligible amount of other trace gases. We’re exposed to nitrogen literally all of the time, we’re just lucky that it exists at nice and comfy temperatures and pressures.
Things get weird, and potentially dangerous, when nitrogen is compressed and cooled. When naturally occurring nitrogen is pressed together and cooled, it becomes liquid, but it has to be very cold. The boiling point of nitrogen is -195.8 degrees Celsius, or -320.4 Fahrenheit. For the more scientifically minded reader, that’s only 77 degrees above absolute zero.
Liquid nitrogen’s incredibly low temperature makes it perfect for a number of useful or at least cool applications. Scientists use it to flash freeze tissues and chefs use it to create interesting effects or rapidly produce ice creams with a smaller than usual crystal structure. As long as you know what you’re doing and you’re operating safely, liquid nitrogen is a perfectly safe resource to use in the laboratory or the kitchen. The reputation for safety, however, is precisely why it can become dangerous. The idea that liquid nitrogen is innocuous has led to some truly unfortunate scenarios in which people have been hurt or killed.
About a decade ago, Jägermeister hosted a pool party and put liquid nitrogen in the pool water to create a foggy atmosphere. Moments after partygoers jumped into the pool, they started losing consciousness. Another incident at a cryotherapy center in Las Vegas resulted in the death of a patron. In both cases, it’s likely the cause of the trouble wasn’t the cold temperatures but the lack of oxygen.
Liquid nitrogen is highly compressed and boils rapidly at ambient temperatures, especially when it’s not maintained in an appropriately insulated container. As it boils and returns to its gaseous state, it expands to fill a comparatively large volume, displacing oxygen. At the pool party, most of the oxygen just above the water was pushed away by nitrogen and the swimmers lost consciousness. Something similar probably happened at the cryotherapy center.
The situation is further complicated by the fact that an individual wouldn’t notice the lack of oxygen. When you hold your breath, the discomfort you feel isn’t from a lack of oxygen, it’s from a buildup of carbon dioxide, something which doesn’t occur when breathing pure nitrogen.
All told, liquid nitrogen is incredibly cold and potentially deadly, both things which work in Jason’s favor.
OKAY, BUT WHAT ABOUT THE SMASHING?
This one comes down to timing and an interesting physical effect. In the movie, we see Jason dunk Adrienne’s head in the lab’s liquid nitrogen container and pull it back out. The whole process is super brief. Using the complex scientific method of running a stopwatch while watching the scene again, SYFY WIRE has confirmed the total dunk time is only 3.5 seconds. That’s not long enough to freeze a head all the way through. It might not even be long enough to kill someone, though we can’t recommend that you test that claim.
If you’ve ever splashed a droplet of water into a very hot pan, you might have noticed it rolls around for a while before settling down and evaporating away. It does that because of a physical process known as the Leidenfrost Effect. When a liquid encounters a surface with a high temperature differential, its exterior immediately vaporizes. That vapor creates a gaseous barrier between the liquid and the surface which briefly protects the liquid from heating and the surface from cooling.
The same thing happens with liquid nitrogen when encountering a warm object. Warm, in the case of liquid nitrogen, is relative. Even a room temperature countertop is warm enough when compared to liquid nitrogen. Living human tissue certainly is.
As a result, when Jason plunged Adrienne’s head into the vat, she would have briefly protected from the freezing temperatures because of the vapor barrier created by the Leidenfrost Effect. To be clear, the protection would have worn off pretty quickly. Three and a half seconds is enough to cause frost burns and all bets are off if she inhaled or swallowed any of the liquid, but it isn’t enough to freeze her head solid.
The subsequent bashing into the countertop might have finished the job, but not in the explosive way we saw on screen, not even with the benefit of Jason’s superhuman strength. We won’t blame Jason for not knowing any better, the educational systems at the bottoms of lakes are notoriously lackluster.
