Question

For Valentine’s Day, Sally received a helium-filled balloon at a party. On returning home she accidentally left the balloon in the car. Later she went to get the balloon and found it was partially deflated. After being in the house for an hour she noticed it was fully inflated again. Explain why this happened.

Answer 1

If the temperature of the air in the balloon is less than the temperature of the air surrounding the balloon then the balloon will appear slightly deflated because of the difference in temperature.

As the temperature of the air in the balloon reaches the surrounding air temperature, then the balloon will appear to be fully inflated because the temperature of the air in the balloon is the same as the surrounding air temperature.