Balloon expands rapidly after being dipped into liquid nitrogen


Fascinating footage shows a balloon inflating after it is taken out of a beaker of liquid nitrogen.

Liquid nitrogen is a cryogenic liquid, a gas that’s kept in a liquid state at extremely low temperatures.

This low temperature causes an air-filled balloon that’s dipped into a tub of liquid nitrogen to shrivel up.   

That’s because cool air takes up less space than warm air does, causing the balloon to shrink.

In the footage, the yellow balloon is lifted out of the tub and placed on the lab surface.

It then starts to inflate when it reaches higher temperatures and the gases inside begin to expand again.

The footage was posted online by a chemistry professor from Florida Southwestern State College who calls herself ‘Chemical Kim’.

‘My focus in teaching science has always been to motivate students to investigate their world through experimentation,’ she wrote in a recent science blog.

Liquid nitrogen, nitrogen that is cold enough to exist in liquid form, has a temperature of -196°C (384°F). 

When it is poured over an inflated balloon it shrinks because the kinetic energy of the gas molecules reduces along with it.

These gas molecules are moving more slowly, which causes them to collide less frequently and less forcefully with the walls of the balloon, which leads to deflation.   

When it is warmed up, the balloon regains its original volume and shape.   

The experiment demonstrates the effect of temperature on volume of gas in a balloon.

The same experiment can be conducted in helium balloons but because helium is lighter than air, it flies up in the air.

The average density of the balloon and helium together is lower than the density of air. 

Just like a piece of wood when held under water, it tends to rise to the surface of the water. 

When the balloon is cooled, the volume of the air is greater, resulting in a greater average density which makes it come back down. 


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