categories:liquid_nitrogen
Liquid Nitrogen Demonstrations
Liquid nitrogen is nitrogen gas cooled to an extremely low temperature, where it becomes a pale liquid at –196 °C. Liquid nitrogen is rarely accessible outside of certain labs or events, so this category collects demonstrations that use it, making the most of the opportunity when the material is on hand.
| Demonstration | Materials | Difficulty | Safety | Summary |
|---|---|---|---|---|
| Liquid Nitrogen Ice Cream | ★★★ | ★★☆ | ★★★ | creamy ice cream is made by rapidly freezing a prepared base with liquid nitrogen, creating very small ice crystals that give it a smooth texture. |
| Liquid Nitrogen Shrinking Balloon | ★★★ | ★★☆ | ★★★ | A balloon filled with air dramatically shrinks when cooled with liquid nitrogen, then re-expands as it warms up again. |
| Liquid Nitrogen Banana Hammer | ★★★ | ★★☆ | ★★★ | A banana frozen in liquid nitrogen becomes so hard that it can be used like a hammer to drive a nail into wood. |
| Freezing a Bouncy Ball in Liquid Nitrogen | ★★★ | ★★☆ | ★★★ | A bouncy ball submerged in liquid nitrogen loses its elasticity because the extreme cold freezes its rubber molecules into a rigid, brittle structure. As a result, the ball cannot compress and rebound, making it unable to bounce until it warms up again. |
| Vortex Rings Using Liquid Nitrogen | ★★★ | ★★☆ | ★★★ | A vortex gun made from a bin or box can shoot doughnut-shaped rings of air called toroidal vortices. By filling the vortex gun with fog created by liquid nitrogen, the normally invisible air rings become visible as dramatic smoke rings. |
| Liquid Nitrogen Teapot | ★★★ | ★★☆ | ★★★ | A whistling-style teapot filled with liquid nitrogen begins to boil vigorously, producing a dramatic fog and whistle sound even in a cold environment such as a freezer. |
| Freeze Antifreeze with Liquid Nitrogen | ★★★ | ★★☆ | ★★★ | Antifreeze is usually a mixture of water and ethylene glycol (or propylene glycol), which lowers the freezing point of the liquid. When placed in liquid nitrogen at –196 °C, it freezes quite easily. |
| Liquid Nitrogen Freezing Marshmallows | ★★★ | ★★☆ | ★★★ | Marshmallows frozen in liquid nitrogen become crisp and brittle. When eaten, the extreme cold condenses the water vapor in exhaled breath, creating a dramatic “dragon’s breath” fog effect. |
| Liquid Nitrogen Hovercraft | ★★★ | ★★☆ | ★★★ | Small pieces of chalk, when frozen in liquid nitrogen, release nitrogen gas as they warm. This escaping gas forms a cushion between the chalk and the floor, causing the chalk to hover and slide across smooth surfaces. |
| Smashing Flowers with Liquid Nitrogen | ★★★ | ★★☆ | ★★★ | When a flower is immersed in liquid nitrogen, the water inside its cells freezes instantly, making the flower brittle. A gentle squeeze or tap causes the petals to shatter into pieces, demonstrating how extreme cold affects living tissues. |
| LED Color Change in Liquid Nitrogen | ★★★ | ★★☆ | ★★★ | When an LED is submerged in liquid nitrogen, its emitted light shifts in color. |
| Meissner Effect | ★★★ | ★★☆ | ★★★ | When cooled below its critical temperature using liquid nitrogen, a superconductor expels magnetic fields and becomes a perfect diamagnet. This phenomenon, known as the Meissner effect, allows a magnet to levitate above the superconductor until it warms above its transition temperature. |
| Liquid Nitrogen Freezing Fruit | ★★★ | ★★☆ | ★★★ | When fruit such as a strawberry or berry is submerged in liquid nitrogen, the water inside its cells freezes almost instantly. This rapid freezing makes the fruit rigid and brittle, so when struck with a hammer or mallet, it shatters instead of squishing. |
| Liquid Nitrogen in Hot Water | ★★★ | ★★☆ | ★★★ | When liquid nitrogen is poured into a beaker of hot water, the nitrogen rapidly boils and chills the water vapor above it. This causes almost every evaporating water molecule to condense into tiny liquid droplets, producing a dense fog. |
| Liquid Nitrogen Volcano | ★★★ | ★★☆ | ★★★ | When liquid nitrogen is poured into warm water, it rapidly boils and expands into gas. Adding bubble mix traps the nitrogen gas, creating a foamy eruption that resembles a volcano. |
| Cleaning the Floor with Liquid Nitrogen | ★★★ | ★★☆ | ★★★ | When liquid nitrogen is poured onto a hard floor, it rapidly boils and skims across the surface because of the Leidenfrost Effect. As it moves, it pushes dust and debris out of the way and can even clear dust from under furniture. |
Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories
Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher
Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff