Here are demonstrations of
some of those
I will add more as time and my liquid nitrogen supply permit.
This page has gotten very large so if
you came to this site to see a particular demonstration this list
may help you find it quickly.
The demos are all on this page so just scroll down and don't bother with the list if you want to see lots of them.
If you are going to try any of the demos please read the precautions in the red text.
Hero's engine, ping-pong ball, heat engine
Frozen balloon, uninflated
Liquid to gas, balloon inflation
Slow chemistry, light stick
Liquid to gas, soap solution
Explosion 1, bucket launch
Modeling clay, broken ball
Liquid nitrogen canon
Magnetic liquid oxygen
Electrical resistance change
Bare light filament
Broken penny, zinc
Balloons in liquid nitrogen
LED band gap change
Solid butane fire
|Wizard ice cream in 12 seconds
Ice cream drops, Dippin' DotsŪ
Clouds, fog, frost and snow
Explosion 2, in a barrel
Lenz's law repulsion coil
Liquid oxygen and fire
Please be very careful if you try any of these demonstrations.
nitrogen is dangerously
Direct contact with the liquid or gas that is boiling off or with materials/containers cooled by it can cause severe frostbite very quickly.
expands more than 700 times
it goes from a liquid to a room temperature gas.
If confined it can produce pressures that can burst nearly any container. Pressures of over 40,000 pounds per square inch are possible.
A pop bottle or a thermos with the lid on is an invitation for disaster
Sealed containers are bombs if there is no way for pressure to be released.
materials become very
and are easily broken when cold.
This includes some steel, other metals, and many plastics.
Don't use untested materials.
it boils nitrogen gas is
It is not poisonous but it will dilute the oxygen content of air thereby reducing it.
If the oxygen level gets too low you will lose consciousness and at still lower concentrations you will die.
Make sure of adequate ventilation during your experiments.
It is possible to make liquid oxygen by condensation of oxygen from the air, even accidentally. This can result in a fire or explosion hazard if the liquid or the high concentration of oxygen gas that results when it evaporates contacts combustible materials. This includes materials that you wouldn't ordinarily think of as flammable. Eliminate all sources of ignition including flames, sparks, and ground apparatus to avoid static discharges.Gloves (even ones designed for cryogenic work) will not provide protection from immersion in liquid nitrogen. If the glove is wetted with the liquid it will soak in and freeze your hand inside the glove.
The temperature of liquid
is boiling at normal
atmospheric pressure is:
77 ° Kelvin
These are just different ways of representing the same temperature. Just like we can measure the same distance in inches, centimeters, miles or other units depending on just what we are doing.
To give you some sense of how cold it is, it is about as much below room temperature as a pizza oven is above it.
Many things change their physical, chemical and electrical properties when cooled to the temperature of liquid nitrogen. The pictures below show some of these effects.
One of the simplest experiments to try is to just spill a few cc's of liquid nitrogen on a hard smooth floor. You will see that each droplet forms a bead and moves quickly around on the floor as if it were frictionless. Close examination of one of the droplets will show that it isn't touching the floor at all. Instead it is sitting on a thin film of gas that is coming from the bead. This is called the Leidenfrost effect, named for a German experimenter who investigated it using water and a hot metal plate in the mid 1700s. The film of gas that is formed is an effective insulator so the evaporation rate is considerably slower than you might expect. The droplets also have the tendency to pick up dust from the surface and as they evaporate the dust is concentrated often forming a tiny ball when the nitrogen has completely evaporated. These pictures show some liquid nitrogen when it was initially poured on a surface and later when dust and possibly frost has collected on it.
Superconductivity can be demonstrated with a disk of yttrium barium copper oxide (Y Ba2 Cu3 O7) ceramic and a neodymium-iron-boron (or other strong) magnet. What you see in the pictures below are the ceramic disk with a small powerful magnet sitting on it. As the disk is cooled by the liquid nitrogen the Meissner effect forces the magnet's field out of the disk which causes the magnet to rise supported by its magnetic field. The magnet is quite stable (if you poke at it it will bob around and return to its starting position). If you do manage to knock it off it can be picked up and set back in place by using non magnetic tweezers.
If you use a pin to poke two holes in a Ping-Pong ball tangential to the surface you can use it to make a Hero's engine. Drop it into a container of liquid nitrogen and hold it under the surface for a few seconds. As the air in the ball cools the pressure in the ball drops and atmospheric pressure forces some liquid nitrogen into the ball. Take the ball out and put it on the floor and as the nitrogen boils and is discharged the ball will spin rapidly. You don't need much liquid in the ball for it to spin so don't try to fill it up. There is the possibility that if the ball is too full the pressure could build up to the point that the ball would burst so don't stand too close when you try this. I have done this experiment many times and haven't had one burst yet but I can't be sure that all Ping-Pong balls can take the pressure.
You can demonstrate how the properties of some materials are changed when they are cooled to cryogenic temperatures.
Here an uninflated long skinny balloon like those used to make animals and such was dipped into liquid nitrogen and then stretched. The kink will break before it straightens. That is not what some might expect for thin and normally flexible rubber.
Here is a still photo
of strips of brass (on left),
to it) and tin (last two) The brass and copper remain
as in the video above the tin became so brittle that it was easily
broken when it was cooled and bent. If you want to repeat this
make sure that you have actual sheet of tin metal not tin plated steel
that is often sold as tin sheet.
When you tap a sheet of lead you shouldn't expect to hear music but when it is cooled to the temperature of liquid nitrogen you can easily hear that the normal temperature dull click takes on a more musical ping.
A spring made from solder doesn't work all that well. When stretched it deforms rather than returning to its original length. The bottom half of this spring was dipped into liquid nitrogen and behaves like you would expect a spring to until it warms up. The top part wasn't cooled and deforms easily and does not come back to it's original shape. This demonstration is more effective if you can find some old lead/tin solder rather than the newer lead free type.
cause chemical reactions to slow down. The
glow of a light stick is quickly extinguished by cooling it.
light returns when the reaction resumes as it warms up. If you cool
only half of the light stick this is what happens. You can
demonstrate this with dry ice or even ice water to a lesser degree.
A simple, dramatic,
messy way to
show the change of volume that
liquid nitrogen undergoes as it changes to a gas is to dump a small
amount of it into a soap and water solution. The nitrogen
and generates a lot of bubbles rather quickly. It helps if
soap solution is warm and you use only a few cc's of liquid
nitrogen. This both makes the change in volume more dramatic
is less likely to result in frozen liquid and
can add more later to see just what frozen bubbles are like.
The old frozen flower trick. Take a flower and dip it in the liquid nitrogen. It looks much the same except for the frost and fog. I usually point out that the flower won't wilt or decay no matter how long it is kept in the liquid nitrogen. In fact it could be studied many years later and would be just as it was immediately after it was frozen. Many types of biological specimens are stored this way to preserve them. However, we have to avoid mechanical damage. To illustrate this I rapidly crush the bloom and let the fragments fall on a hard surface. Usually someone will say that they sound like broken glass. You can crush the flower with your bare hand if you release it very quickly and use a flower that doesn't have a lot of places that the liquid could be trapped. Chrysanthemums are a particularly bad choice.
Liquid Nitrogen Explosion
A ball of modeling
will freeze and
when dropped or struck will
shatter nicely. There are a lot of different kinds of clay
available and some probably will be harder to break than
If you discover one that is particularly durable let me know about it.
During a demonstration of the properties of liquid nitrogen I was challenged to a duel. The canons were loaded with a gallon of hot water and Styrofoam packing peanuts. At the count of three the combatants dumped liquid nitrogen into their canons. It boiled rapidly and you see the results.
Here is a way to produce a few drops of liquid oxygen. Put liquid nitrogen in an aluminum can. The outside of the can will quickly cool to just above the temperature of the nitrogen. Frost will quickly form and then it will appear to be wet. The frost is created from water vapor from the air. The liquid that is wetting it is oxygen that is condensing out of the air. This happens because the temperature at which oxygen changes from a gas to a liquid is about 13 degrees Celsius above that of nitrogen. The oxygen can be seen dripping from the can just as on a humid day you can see drops of water condense and drip from a can you take from the refrigerator. Be sure to observe the special precautions for liquid oxygen in the red text at the top of the page.
Liquid oxygen is magnetic. I filled a
nonmagnetic aluminum container with liquid oxygen then brought a strong
magnet near to it.
You can see it is attracted to the magnet.
The resistance of most conductors goes down as the temperatures falls. Here is a flashlight bulb connected to a battery through a coil of wire. At room temperature the resistance of the coil is high and the bulb barely glows. When the coil is cooled the bulb gets much brighter.
electricity/light experiment I removed the glass from a 12 volt light
bulb and immersed it in liquid nitrogen and powered it up. If I
did this in air it would immediately burn out but the nitrogen prevents
oxygen from getting to it so it continues to work. It may be
surprising that the filament is able to become incandescent even though
it is being cooled by the liquid nitrogen but the Leidenfrost effect
shown at the top
of the page provides enough thermal insulation for it to work.
This picture shows the bare filament with a wire cage around it to keep
it from being broken if I happen to bump it into the liquid nitrogen
Break a penny? US pennies minted after 1983 have a zinc core clad with a very thin coat of copper. Prior to that time they were solid copper. The zinc becomes brittle when cooled in liquid nitrogen and can be broken by tapping it with a hammer. At room temperature they remain intact as do the solid copper ones at either temperature.
container of liquid nitrogen will
slowly collapse as the air inside it contracts and condenses.
part of the balloon that is cooled becomes quite stiff and crinkles
a plastic bag. When it has nearly completely deflated you can
it out and show the liquid air by swirling it in the bottom of the
If you haven't cracked the balloon by bending it when it was frozen and
is a reasonably large part of the balloon that isn't so hard that it
stretch, it will reinflate to it's original size demonstrating that all
air is still in there.
marshmallow on a stick and freeze
it. Marshmallows are
insulators so they take a couple of minutes to freeze. Take
and rap it on a hard surface and it will shatter. I recommend
you don't do this where it will be hard to clean up because those
of marshmallow will quickly warm up and they are incredibly
(The first time I did this it was in my kitchen and my wife hasn't
ball. The solid
high bouncing rubber balls
bounce on hard surfaces but they sound like marbles or pool
type balls are easily broken but if you decide to do that be aware that
the fragments can fly quite a distance and could hurt if they hit
Make a candle from
vegetable oil or any
When frozen most will look a lot like
paraffin. Alternately dip a wick into the liquid and into the
When you get a reasonable size candle you can put it in a holder and
it. Of course as it burns and warms from the air it will
liquefy and you will have an oil lamp with a long wick that may fall in
any direction. Please be aware of the potential fire hazard
appropriate precautions. The white candle was made using
vegetable oil and the greenish one was made from gasoline (use extreme
A lump of solid butane was made by cooling a container of butane with liquid nitrogen. The lump was put on a piece of cardboard and ignited. Because the evaporation of the butane cools the cardboard the cardboard doesn't catch fire. The only change is some soot deposited on it.
cream. Use any good
homemade ice cream recipe. Put it in
a metal bowl and add about an equal volume of liquid nitrogen while
vigorously with a wooden spoon. You won't be able to see what is going
on in the bowl because of the vapor cloud that is produced.
record time for going from liquid
to finished product is 12 seconds for a half gallon of ice
Be sure that you don't use too much liquid nitrogen. If you
the ice cream will be rock hard and if you manage to serve some there
will be a real chance of frostbite of the tongue.
You can make
tiny ice cream
dripping the mix directly into
a container of liquid nitrogen. It doesn't make much very
it is an interesting product similar to Dippin' DotsŪ.
nitrogen will freeze into a
of ice with liquid water inside. The balloon may split
because it becomes brittle and the water expands as it turns to
ice. The picture shows a hole chipped in the ice shell to see
the center was still liquid. It was.
if you can be sure that no
one will mistake them for a cup of beverage. You shouldn't
of beverage in any laboratory setting in any case.
pop bottle that has
been cut off near the
top of the wide part also makes a good container for liquid
It can be seen to be boiling looking through the side of the
The cloud that forms and cascades from the bottle is like formation of
clouds when warm moist air is cooled by rising to higher
where it is cooler. Fog is also formed when the
by radiation of heat into space and it cools the air and the moisture
out. If you tap on the bottle the frost that has formed on it
fall off and feels just like snow so you have a few elements of a
demonstration. It is a good idea to use a sheet of styrofoam to
insulate the surface where you set the container to keep it from
cracking because of the cold.