3 coolest science experiments and tricks with balloons you can do at home for kids.
Youtube video: 3 Amazing Science Experiments with Balloons
Liquid nitrogen has a temperature of -196 degree Celsius. When cooled by liquid nitrogen, the balloon shrinks and it sinks down in the bucket. The balloon stays large because the elasticity is frozen out of it. Once the balloons start warming up you see the air expanding again and the elasticity returning.