Frozen Balloon

We lower a helium-filled balloon into liquid nitrogen to see how the change in temperature affects its volume. When it hits the cool liquid nitrogen, the gas inside contracts and the volume of the balloon decreases. When it is removed and returns to room temperature, the gas inside expands and the volume of the balloon increases. Physics - Forces - Learning Points. The pressure, volume and temperature of a gas are all connected. The volume of a gas changes with temperature if the pressure is kept constant. A Twig Experiment Film. Let students experience real experiments in lab conditions anywhere, from setup, method all the way through to analysis and real-world application.