Pressure II Segment 3: Pressure Differences

What do you get when you mix balloons, liquid nitrogen, and eager young scientists (equipped with proper safety gear, of course)? It sounds like another exciting EveryDay Science experiment! As we saw in segment 2, heat and pressure are related. Brian, Ellis and Grace have set up a demonstration of just how dynamic pressure and temperature can be. Liquid nitrogen is at about -200 degrees Celcius, and boils at -196 C, so when it is introduced into room temperature air (about 20 C), it boils without fail. As the nitrogen becomes a gas, they use it to fill balloons. They then put the balloons back into the liquid nitrogen, which cools the nitrogen inside the balloons, reducing the inside pressure and shrinking the balloon. Removing it warms the inside and it expands once again.