Tag Archives: Liquid Nitrogen

Liquid Nitrogen Cloud

Okay, maybe that’s a silly way to look at this. Clouds are made up of tiny water droplets, so “instant cloud: just add water” makes about as much sense as the old joke, “powdered water, just add water”.

What we actually have here is liquid nitrogen. Liquid nitrogen is very cold, checking in at -321 degrees Fahrenheit. Even just pouring it out on the ground creates clouds of water vapor, because its cryogenic temperature causes water molecules to condense in the air nearby.

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In this demonstration, we intensify the condensation process using very hot water. The molecules in the hot water have lots of energy, so the liquid evaporates into a gas more easily than it would at room temperature. This creates humidity in the air nearby, leading to a more impressive cloud.

When hot water is rapidly introduced into liquid nitrogen, the nitrogen ceases to be a liquid and almost immediately becomes a gas. This is because that very cold temperature mentioned before is actually its boiling point. Raise the temperature of nitrogen above -321F, and the liquid boils away. The water doesn’t cool down as much as you might expect because it has a high specific heat (it’s difficult to change its temperature). In other words, it takes a lot of energy to heat water up, but not very much to vaporize nitrogen.

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As you can see, our brave instructor Paul is just fine after the whole ordeal. The liquid nitrogen evaporates immediately, and the water is just hot tap water, so the worst treatment he receives is a shower!

Liquid Nitrogen & Glowsticks

Note: Opening glowsticks is not a particularly great idea. They contain bits of broken glass and some unpleasant chemicals that can be hazardous to your health! Read full article to learn more.

Glowsticks are incredibly fun, but how do they work!? Naturally because of some very cool science, notable chemistry. Glowsticks are made up of an outer plastic casing with a smaller glass casing inside. The plastic tube is filled with a dye which determines the color of the glowstick and a chemical called diphenyl oxalate. The glass tube contains hydrogen peroxide, the same thing you might use to clean out a cut or scrape.

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When you crack the glowstick you break the glass, the hydrogen peroxide is released into the mixture. This causes a series of chemical reactions to take place. The main end products of this chemistry are carbon dioxide and energy, as well as another molecule we will talk about later. The energy that is released goes into the dye, which converts the chemical energy into light energy! The reaction happens slowly, so that the glow lasts for a long time. Companies can vary the amount of each chemical to have glowsticks that glow brightly for a short time or more dimly for a very long time!

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It also forms something called phenol that is a somewhat toxic chemical. Repeated exposure to this chemical, and even its vapors can be dangerous. This is why breaking open a glow stick without proper protection is not advisable. There will be phenol and broken glass in the mixture, neither of which are good things to have around! We were very careful, and used protective equipment on our skin as well as working in a well ventilated area to keep ourselves safe!

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One interesting thing is that this reaction can be stopped by extreme cold. Check out what happened when we left the glowsticks in liquid nitrogen for a while! Science!

What to Freeze Series – Cryogenics

 
CAUTION: DO NOT TRY THIS AT HOME! LIQUID NITROGEN CAN CAUSE TERRIBLE BURNS! (Death of living tissue caused by the extreme cold.)

Liquid Nitrogen can be scary. We call it a cryogenic fluid because it can rapidly cool substances down to temperatures around -321 degrees Fahrenheit. Unprotected human body parts are not immune to the danger at all. The water in our body will cool down rapidly and cause them to freeze solid, to the point where they could potentially break. That’s where we got the idea to pull this little maneuver, but with a banana in the glove instead of a finger. Just be warned though, we are professionals that know the limits of liquid nitrogen and how far to keep it away from our bodies. Please do not try this at home!!

But in science fiction, cryogenic substance like liquid nitrogen have a long and storied history; mostly being used to put humans into a deep freeze from which they can awaken many years in the future. Cryostasis as it would be called, could be very convenient for a couple of reasons: it could preserve astronauts on interstellar voyages that would normally last longer than a human lifespan, or perhaps preserve a person dying of a terminal illness until the cure is discovered. This type of technology could be very useful if it ever proves feasible. Studies have shown that if the cooling is done slow enough living cells can be preserved using this method. So perhaps we’ll see the first cryogenic human in our lifetime. Sorry to disappoint the conspiracy theorists out there, but Walt Disney is not currently frozen in liquid nitrogen. That’s just a rumor.

In “The What to Freeze Series” we will experiment with freezing different objects. What do you want to freeze next?

Liquid Nitrogen Pool Exploration

CAUTION: DO NOT DO THIS WITH SOMEONE IN THE POOL! IT IS VERY DANGEROUS AS THE EVAPORATED NITROGEN DISPLACES THE OXYGEN IN THE AIR AND SOMEONE COULD SUFFOCATE AND POSSIBLE DEATH.

At AstroCamp, we love exploring and testing theories. So what do we do when we have excess liquid nitrogen from our summer camp program that will evaporate before we can use it again?  Why we do some experiments of course!  Our favorite recent experiment was dumping the left over liquid nitrogen into the pool.  We thought we were going to get a lot of condensation from the water vapor coming into contact with the cold liquid nitrogen.  What we forgot to take into account was the Leidenfrost Effect.  The Leidenfrost Effect occurs when a liquid comes into contact with a surface much hotter than it.  Because of the drastic change in temperature, the liquid that comes into contact with the surface boils near instantly.  But the boiled gas creates a buffer for the rest of the liquid and keeps it from evaporating for a while longer. In the pool, this allows the liquid nitrogen to spread across the surface of the water, expanding the fog until it nearly covers the pool entirely.  Stay tuned for future fun things to do with liquid nitrogen exploration!

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