Where to get liquid nitrogen, what it costs, and how to not hurt anyone.
This is the question that stops most people buying a superconductor kit. The honest answer is that liquid nitrogen is cheaper, more available and less exotic than nearly everyone expects — and that it does need to be treated with respect. Both things are true.
* In the US, UK and EU. Suppliers may still require a trade account and evidence of a suitable dewar.
Air, with the interesting parts removed.
Liquid nitrogen is ordinary atmospheric nitrogen — 78% of the air you’re breathing — cooled until it condenses at 77 kelvin, or −196 °C. It’s produced industrially in enormous quantities as a by-product of separating oxygen from air, which is why it costs roughly what milk costs.
It is non-toxic, non-flammable and chemically inert. It won’t corrode anything, react with anything, or poison anyone. The hazards it does have come entirely from two properties: it is extremely cold, and it expands enormously when it warms up.
For superconductor work it’s the ideal coolant. YBCO becomes superconducting below 92 K; liquid nitrogen sits at 77 K, comfortably underneath, with fifteen degrees of margin. Conventional superconductors need liquid helium at 4 K — vastly more expensive, harder to obtain, and requiring a cryostat rather than a polystyrene tray. That gap is the entire reason a tabletop quantum levitation demonstration is possible at all.
Four places that will sell you some.
In rough order of how likely they are to work for you. Prices vary considerably by country and by whether you’re collecting or having it delivered.
Industrial & welding gas suppliers
The default answer nearly everywhere. Airgas and Praxair in the US; BOC in the UK and Ireland; Linde and Air Liquide across Europe and much of Asia. Every industrial town has a depot.
- Cost
- $0.50–$2 / litre collected
- Minimum
- Usually a full dewar fill
- Catch
- May want a trade account and proof you own a proper dewar
University stores or physics departments
Almost every university with a physics, chemistry or biology department has liquid nitrogen on tap, usually from a bulk tank. If you’re at one, or can befriend someone who is, this is far and away the easiest route.
- Cost
- Often free or near-free internally
- Minimum
- Whatever you can carry
- Catch
- Internal users only, generally
Ice cream shops and specialist caterers
Nitrogen ice cream is made by the litre. Plenty of independent shops will fill a dewar for a small charge if you turn up with one and explain what it’s for — teachers report a high success rate.
- Cost
- Often $10–20 for a few litres
- Minimum
- Whatever they’ll spare
- Catch
- Entirely at their discretion — call first
Vets, fertility and dermatology clinics
Cryopreservation and wart removal both use liquid nitrogen, so small clinics keep dewars. Not a route to large volumes, but a possibility if you need two litres for a one-off demonstration and everything else has failed.
- Cost
- Varies wildly
- Minimum
- Small quantities only
- Catch
- Many will decline on liability grounds
Find a supplier near you
Searches Google Maps for liquid nitrogen and industrial gas vendors in your area — the most reliable source in most countries.
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Less than you think, but it doesn’t keep.
Cooling a single levitator disc takes remarkably little — perhaps 100–200 ml poured into a shallow tray, most of which boils off during the cooling itself. The disc reaches 77 K in under a minute and then holds its superconducting state for three to fifteen minutes depending on the kit.
Where consumption adds up is repetition. A single demonstration to a lecture theatre might use half a litre. A hands-on session where thirty students each cool and re-cool a levitator over ninety minutes will comfortably get through two litres, sometimes three.
Rough planning figures
- One demonstration, one levitator: 0.2–0.5 litres
- A single lesson, teacher-led: 0.5–1 litre
- A class of 30 in small groups, 90 minutes: 2–3 litres
- A museum running three shows a day: 3–5 litres daily
- A science fair stand, full day: 4–6 litres
Never sealed. Never in a lift with people.
Both of those rules follow from the same fact: 1 litre of liquid becomes 694 litres of gas.
Never seal a container of liquid nitrogen. A dewar has a loose cap that lets gas escape while keeping warm air out. Fit a tight lid and you have built a bomb — this is not hyperbole, sealed cryogenic containers have caused serious injuries and structural damage. If a container doesn’t vent, don’t put liquid nitrogen in it.
Never travel in an enclosed space with an open dewar. That means no lifts with passengers, and not in the cabin of a car. Nitrogen gas is odourless, colourless and gives no warning whatsoever — it simply displaces oxygen. In a lift or a sealed car, a spill can reduce oxygen concentration to dangerous levels within minutes, and the first symptom of oxygen deficiency is impaired judgement, which means you may not recognise what is happening to you.
Storage checklist
- Vacuum-insulated cryogenic dewar, loosely capped, upright
- Well-ventilated room — not a cupboard, not a small store room
- Stable surface where it can’t be knocked over
- Away from where students pass or congregate
- Signed, so nobody moves it or investigates it
The rules that matter.
Liquid nitrogen is handled routinely by teenagers in university open days and by ice cream vendors in shopping centres. It is manageable. It is not casual.
- DoWork in a well-ventilated room
Ordinary classroom ventilation is fine. Basements, cupboards and sealed labs are not.
- DoPour slowly, at arm’s length
Fast pouring onto a warm surface causes violent boiling and splashing.
- DoUse the tweezers supplied
For moving the superconductor while it’s cold. Never fingers.
- DoLet spills evaporate
A small spill on the floor boils off in seconds and is harmless. Don’t mop it.
- DoBrief everyone in the room first
Including the adults. Especially the adults.
- NeverSeal it in any container
Pressure builds until the container fails. This is the one that causes serious injuries.
- NeverTouch cold metal with bare skin
Cold metal bonds to moist skin instantly. The tweezers are not optional.
- NeverPut it in your mouth or swallow it
People have been very seriously injured by cocktails and snacks served before the nitrogen fully boiled off.
- NeverWear it — no open shoes, no watches, no rings
Anything that traps liquid against skin turns a splash into a burn.
- NeverLeave it unattended around children
It’s fascinating, which is exactly the problem.
Personal protective equipment
Eye protection
Safety goggles or a face shield. Boiling liquid splashes, and an eye has no protective reflex fast enough. A face shield is better if you’re pouring larger volumes.
Cryogenic gloves
Loose-fitting, so you can shake them off instantly if liquid gets inside. Ordinary lab gloves are worse than useless — they trap the liquid against your skin.
Closed shoes, long trousers
Trousers worn outside the shoes, not tucked in, so any splash runs off rather than collecting. No sandals, no bare ankles.
Lab coat or apron
Long sleeves, unbuttoned cuffs. Mostly this is about avoiding a splash reaching your forearms.
Tongs or tweezers
Supplied with every kit. For anything that has been in contact with the liquid.
Oxygen monitor
Only necessary for substantial quantities in confined spaces. A classroom demonstration with two litres does not need one.
If something goes wrong
Cold burn on skin. Flood the area with lukewarm — not hot — water for at least fifteen minutes. Do not rub. Do not apply direct heat. Seek medical attention for anything beyond brief redness; cold burns are assessed like thermal burns.
Someone feels dizzy or confused. Get them into fresh air immediately and ventilate the room. Oxygen deficiency impairs judgement before it produces obvious distress, so treat confusion as the warning sign, not as an overreaction.
Large spill indoors. Leave the room, prop the door open, and let it ventilate for fifteen minutes before returning. The visible fog is condensed water vapour, not nitrogen — the nitrogen itself is invisible, so the fog is a poor guide to where the gas actually is.
Getting it past your safety officer.
Teachers tell us this is the step they dread and it’s usually the easiest. Liquid nitrogen is not an unusual request — it is used in schools for cryogenics demonstrations, in universities constantly, and in food service publicly. Your safety officer has almost certainly seen a request before.
What tends to work:
- Go early, with a written plan rather than a verbal request the week before
- Name the quantity. “Two litres, used within one hour, in room 14” reassures far more than “some liquid nitrogen”
- Specify the ventilation and the PPE you’ll have on hand
- Say who handles it. Most approvals are conditional on the teacher pouring and students only observing or handling the already-cooled superconductor — which is fine, and loses nothing pedagogically
- Include the supplier’s safety data sheet, which they’ll provide on request
We supply a pre-filled risk assessment template covering the hazards, controls and emergency procedures for exactly this scenario. It’s written for a teaching setting rather than an industrial one, so it should need editing rather than writing from scratch.
Risk assessment template
Pre-filled for liquid nitrogen use in a classroom or outreach setting — hazards, controls, PPE, emergency procedures and a sign-off block. Editable, and written to be handed straight to a safety officer.
Some of this is optional.
If the cryogenics is the obstacle, several kits demonstrate magnetic levitation using permanent magnets alone — no liquid nitrogen, no PPE, no risk assessment. They show less physics, but they show it to anyone.
| Kit | Liquid nitrogen | What it demonstrates | From |
|---|---|---|---|
| Magnetic Train Science Fair Kit | Not needed | Magnetic repulsion, stable levitation via geometry | $69 |
| Magnetic Levitation Kit — DIY | Not needed | Magnetic repulsion, track building | $69 |
| DIY Maglev Desktop Toy | Not needed | Magnetic levitation, hands-on play | $69 |
| Handheld Magnetic Device | Not needed | Field interaction, group work | $299 |
| Chladni Plates Kit | Not needed | Standing waves, resonance — different physics entirely | $549 |
| YBCO Meissner & Flux Pinning Disk | Required | Quantum locking, flux pinning, Meissner effect | $349 |
| Economy Superconductivity Kit | Required | Quantum locking, frictionless motion | $139 |
| Quantum Locking Starter Kit | Required | Full flux pinning demonstration with track | $587 |
| 4-point Tc Setup | Required | Quantitative resistance-vs-temperature measurement | $587 |
| Mini Maglev Kit | Required | Circular maglev track, sustained levitation | $1,497 |
Asked often.
Do I need a licence to buy liquid nitrogen?
No, not in the US, UK or EU — it’s an ordinary industrial gas, not a controlled substance. What suppliers often do require is a trade account and evidence that you own a proper cryogenic dewar, which is a commercial and liability precaution rather than a legal one.
Rules elsewhere vary, so check locally if you’re outside those regions.
Can I use dry ice instead?
Can students handle the liquid nitrogen themselves?
That’s your institution’s decision, not ours, and most approvals we hear about have the teacher pouring while students handle the already-cooled superconductor and the magnets.
Pedagogically you lose very little. The memorable moment is the magnet locking in mid-air, not the pouring.
How long does a dewar of liquid nitrogen last?
Is it dangerous to breathe near it?
What if a student puts their hand in it?
Brief contact with liquid nitrogen often causes no injury at all — the Leidenfrost effect creates an insulating gas layer, which is why you sometimes see people pour it over a hand as a party trick. We would strongly discourage relying on that.
Sustained contact, or contact with cold metal, causes serious cold burns quickly. Treat any contact with lukewarm water for fifteen minutes and get medical advice for anything beyond brief redness.
