How to Make a Liquid Nitrogen Rocket

by kentchemistry.com

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Intro: How to Make a Liquid Nitrogen Rocket

Liquid nitrogen explodes a soda bottle in just a few seconds. Enough to send a bucket a few hundred feet into the air.

The set up
a strong 5 gallon bucket (no handle), a metal bowl filled 1/2 way with water, a 1 liter plastic bottle

fill 1/8of the plastic bottle with liquid nitrogen and cap (****note this is not a bomb)
quickly place in the bowl with water and cover with the bucket
move away

***Another Note- never look under the bucket

31 Comments

rocketman217 14 years ago

in a fire extenguisher the c02 goes through sublimination which is liquid-solid instantly and can only stay liquid if pressurized.

flamekiller 14 years ago

I know it's been six months but I feel a comment is necessary for all the junior chemists out there.  Sublimation is the transition from solid to gas, bypassing the liquid phase.  It's what dry ice (solid carbon dioxide) does, and is most easily demonstrable by dropping a chunk in water and observing the bubbles coming off of it. 

CO2 fire extinguishers precipitate a dry ice "snow" created when the gaseous CO2 in the extinguisher dumps its heat as the pressure drops.  This snow then sublimates into the gaseous phase. 

As for where to find liquid nitrogen, first educate thyself.  It's very (very) cold and can cause severe thermal injuries if not handled properly (this means thick gloves, approved goggles, possibly facial protection, and tongs).  LN2 also expands to about 700 times its volume when it boils off, meaning placing it in a sealed container creates risk of explosion, and allowing it to boil off in a small, sealed room creates risk of suffocation.

It's not rare, toxic, or illegal.  It can be had at a gas or welding supply shop for probably around the price of milk.

Bowtie41 14 years ago

Finally,an educated reply.We purchased ours from Air Products,which sells all sorts of welding gasses.We also used it in metalforming.A place I used to work made stainless steel fittings.In order to bend them to 90 degress without splitting,we threw them in a foam cooler with a couple inches of liquid nitrogen.Then they bend like copper.Another shop I worked at we chilled titanium bars so they could be machined easy.Once they got to room temperature the tooling would quickly wear down.

.(((QUICKSILVER))). 15 years ago

and ware exactly would i get liquid nitrogen? im pretty sure its illegal

bigbodysmallbrain 14 years ago

illegal nah ,
just beg the local high school ( may only work if you are a student in a cool teachers class though

wizkid95 14 years ago

To buy liquid nitrogen all you have to do is go to a welding store. Like Norco for example. It's not illegal, just like dry ice isn't...

senojjones 15 years ago

you cannot liquify nitrogen with dry ice. Not aware of any retail source that will sell liquid nitrogen to tourists. I suspect someone knows someone who works in a research lab.

drawe21 15 years ago

Liquid Nitrogen is -320 degrees below 0 Fahrenheit , or - 195.5 Celsius. Very cold stuff, I have worked with this often. (You should see what it does to a frog)

senojjones 15 years ago

You can liquify nitrogen just like you do freon, with a compressor. Don't think you can do this with anything you can buy at Home Despot. You could probably pull it off, if you were interested in spending the money and time. I have other fish to fry. Practically speaking, you need a commercial source, or know someone who works in a hospital or science lab. We used to play with the stuff. And yes, it's really hard on frogs..

dla888 14 years ago

You can actually stick your hand in a vat of liquid nitrogen for a few seconds. This is true because your hand is so warm it causes the liquid nitrogen to evaporate. Pretty cool(bad pun), eh?

Also if this might help with the dilemma of finding liquid nitrogen, It is often used in the manufacture of aircraft parts (tubes and gaskets, I believe). If you work in a aircraft parts factory, you might be able to score some.

Bartboy 15 years ago

not illegal, just rare.

szechuan53 15 years ago

but seriously, where did you get it? i know how to make it out of gaseous nitrogen, but i don't have that either

BOXHARD 15 years ago

Use dry ice... I think that's what he meant anyway... It's frozen (liquid) Nitrogen...

szechuan53 15 years ago

well, know i know where to get gaseous nitrogen now, but thanks anyway. hooray for air compressors!

BOXHARD 15 years ago

I was having a brain fart on this whole topic... my apologies to all...

jlmowery 15 years ago

No it's not. Dry ice is solid (frozen) carbon dioxide. Not the same thing at all.

BOXHARD 15 years ago

Ur right... two different things... I guess it hadn't occurred to you that gasses have to first go into a liquid state before they freeze. That's chemistry for ya... go figure...
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